Frequently Asked Questions:  Please read ALL of these before calling!

Q: What are the types of air-cooled 3.6s?

A: Click here for 3.6 engine variants

Q: Besides an engine and the basic conversion kit, what else will I need?
A: Oil Cooler Upgrade and an Exhaust System

  • You will need to upgrade your oil cooling system to either two fender coolers or one nose mount cooler.
  • The 964 engine’s exhaust is terrible and will not clear the transmission.
  • The 993 heat exchangers will work but you will still need a muffler, like our Happy Crab.

Q: How much HP will the car make?  Will I notice a difference?
A: Oh yeah!  The following are from actual dyno measurements or Porsche data:

  • 3.0 SC 180-190 HP
  • 3.2 Carrera 217
  • C2 3.6 with stock chips and exhaust: 247 (Porsche, used as a base line for the following measurements)
  • C2 3.6 with Cyntex chips 263
  • C2 3.6, Cyntex chips, 993 Happy Crab Exhaust 275
  • C2 3.6, Cyntex Chips, McNeil headers, Dual in-dual out muffler 285
  • C2 3.6, Cyntex Chips, 1-3/4″” headers, dual 2.5″ stainless Supertrapps 288
  • 993 95 Headers, Supertrapps, 289
  • 993 3.6 Varioram , Cyntex Chips optimized for Varioram, Headers, Supertraps 298, 305 with open exhaust, but read about the whole VarioRAM story here

Q: How about a 3.0/3.2 conversion for an early car? Isn’t that a lot cheaper and almost as good?
A: Cheaper:Yes.  Just as good: No. What’s better really depends on your  budget.

  • The 3.0 / 3.2 conversion is substantially less expensive, and few conversion parts are required if the engine is purchased “complete.”
  • A decent used 3.0 runs about $6,000-$7500 and makes 180 to 190 HP depending on year.
  • A decent 3.2 will run you about $7,500-$10,000 with DME and makes 217 HP, maybe 235 with better exhaust and a set of chips which can add substantially to the price.
  • These engines are now 26 to 36 years old so make sure you’re not buying someone else’s problems!
    • Look out for broken head studs, leaky heads and worn out valve guides on even “low mileage” motors.
  • If you go this way, get a 3.2. The extra cost is well worth it for the engine management alone. CIS can be very expensive to diagnose and repair, and ethanol/old gas can cause thousands in damage.
  • We often have packages available since we have leftovers from all the 3.6 conversions!
  • How about hot-rodding a 3.2? Won’t that be just as good?

Q: What are the differences between 993 and 964?
A: There are many differences between the 964 engine and the 993.

  • Click here for a detailed explanation
  • The VarioRAM is only available for 993 Engines.  It is by far the biggest performance improvement for the 3.6. Read about that here.
  • Be careful of Early 964 engine, head gasket failure is described here.
  • Other than that, the easiest approach is to compare a 1992-1994 964 to a 993.
    •  Intake Manifolds: Virtually the same. 993 has 1mm larger runners.  Worth 2-3 HP.
    • Air Flow Meter:  the 993 has a mass flow whereas the 964 has a “barn door” flapper.  Worth 2-3 HP
    • Rockers:  The 993 has hydraulic rockers.  They never need to be adjusted and are quite reliable.  On the other hand if the car is a pure race car and spends most of its life above 5000 RPMs or you ever think of changing to lumpy cams, you’ll be better off with solid lifters.
    • Exhaust – the 993 has separate right and left exhaust headers which join in the center and a highly efficient dual catalyst. This is where the bulk of the 25 horsepower change comes from.
    • Crank/Rods – the 993 has a stiffer and lighter crank assembly.
      • The crank is heavier but it doesn’t need a harmonic balancer, something to think about for all those lightweight crank-pulley fans.
      • It also has lighter rods, but narrower rod bearings.
      • Are the narrower rod bearings a problem?  Apparently not since the GT3 uses the same bearings and crankshaft!
    • Valves: 993 Varioram engines (both US and European) have 50mm intakes and 43.5mm exhausts.  All others have the same size valve as a 3.0/3.2 49mm/41.5mm.
      • This seems to be worth 8-10HP on paper since at the top end the VRam and 95 993 engines are essentially the same, in reality it’s difficult to even measure.

Q: What’s a VarioRAM and why should I care?
A: VarioRAM engines differ from 993 engines in two respects:

  • The intake manifold is completely different.
  • The valves are larger.
  • If you just want the bottom line then the Varioram makes only 3.5% more peak power.  On the other hand it makes 20% more torque at 4000 RPM!
  • VarioRAM Explained click here.

Q: Which engine is best?  What about 993 engines?
A: The most popular were the 1991-1994 964, but now 993 enignes are.  Any 3.6 engine can be installed.  It’s more important to get a good engine than any specific engine.

  • There are two basic engine types, 964 and 993.
  • 964 is 1989-1994 and early engines (through 1991.5) can be distinguished by the aluminum intake.
  • 993 engines add hydraulic lifters, and a redesigned crank and rods–and come in two basic flavors as well.
  • Click here for full details

Q: What about a 3.8?
A: If you have a motor that needs a rebuild then go for it, otherwise, it’s a lot of money.

  • Displacement means more power.
    • a 3.6 is 76.4x100mm = 3600 cc.
    • 3.8 is actually 76.4x102mm = 3750 so it’s actually a 3.75 ltr.  That’s 4%.
    • So let’s say you have a varioram and we say it makes 300HP.
    • Now multiply by 104% and you get 312.  Those can be 12 very expensive horsepower.
  • The factory 3.8 street motors, with bigger ports, valves, and intake manifolds were rated at 300 HP, 18 more than the 3.6.  The extra 6 HP is attributable to the RS cams and more aggressive tuning on the chips.  In reality that’s bologna, the factory 3.8 made at least 330 HP.  They were detuned for regulatory reasons.
  • This can get expensive.
    • You can do slip-fit cylinders ($3500 or so), port and modify the heads with larger valves ($1000+), buy the varioram down tubes and injector stacks ($800), a set of euro RS cams ($800) and pay for a top end rebuild ($2500 -w- machining?) assuming you have a decent bottom end and you’ll be $8500 or so poorer.  Ouch.  Maybe you get 20 more horsepower.  Just slapping in P&Cs is also a way to go.  That’s OK if you have to do it anyway, like on an early 964 motor with early P&Cs, but you still have to machine the heads.  We also weld them to strengthen the perimeter.
    • If you are going to do it right, like an RSR then you need to do some more things. You have to bore the case 2mm to accept the more robust cylinders, you need to weld up the heads, and maybe think about some larger valves.  When you hear 375 HP out of the RSR 3.8s then you are talking much wilder cams, so much so that you cannot use a mass flow, you do throttle-speed-density like the RSRs did and you are in a different ball game.  56mm intake valves with 44mm exhausts and some decent valve springs and retainers.  At that point you may as well call CMW and get their heads and 104mm cylinders and forget about the budget, you’ll be running race gas anyway.
    • Bottom line:  We recommend it only if you are going to rebuild a motor anyway.  While the extra displacement may not justify it, the extra bragging rights might!  We saw about 18 HP difference over the 3.6 varioram on an engine that had “warm” hydraulic cams and RS 51.5mm intake.  Those are very expensive ponies considering the upgrade and rebuild was pushing $10K over the price of a varioram.
    • Click here for the truth about 3.8s

Q: Can anyone do this, or do I need an expert in 3.6 conversion?  How long will it take?
A: Anyone competent in engine removal and replacement can perform this conversion.

  • Figure on 15-20 hours plus whatever it takes to remove the 3.6 exhaust. When I did my first conversion, I was met with nothing but frustration.  The vendor from which I purchased the parts (you can guess, because he makes the flywheels) was less than helpful.  I didn’t know which parts were needed, how to rewire the harness, move the pins in the connectors, etc.  It ended up taking me, who has done a fair amount of 911 work, over two weeks, and the engine still had problems starting, fuel leaks, etc.
  • After consulting with the guys at Cyntex, and actually taking the car up there, we got all the bugs worked out (you can get a feeling of this from the notations on the BlauCarrera page, which was done during the first conversion).
  • I decided that it would be best not to put the rest of the 911 world through this HELL, so I developed this kit.  I got someone local to make wiring harnesses (since the one I had purchased was assembled with some pins in the wrong place, which is why the car would not start!) and decided to offer this kit.  Is it a big money maker? No.  Not when you take into account tech support and all the people who pick my brain then buy the parts somewhere else.  Here’s the history
  • The kit includes COMPLETE instructions and tech support.  Right down to which pins to move in the engine connector to keep from frying your wiring harness, and five pages of detailed instructions.  All modifications (engine cross member, sheet metal, etc.) are done here at Instant-G to eliminate any guesswork.
  • Bottom line:  you can do it yourself or have your local Porsche shop do the work.  We charge about 20-25 hours on the average job, which includes cleaning up the 3.6, adjusting the valves, and removing the exhaust system.  Again, a lot depends on the exhaust system chosen.  Some are custom fabricated.  If you buy a crate motor, count on 10-15 hours since the hard part is done.  We have done conversions in as little as 6 hours, but I am quite good at it!  If the conversion is done in house with one of our crate motors in house we generally charge 12-15 hours, more if heating plumbing and/or oil coolers are required.

Q: Which other parts do I have to buy?
A: You must supply the following: Clutch, throw out bearing, pressure plate (from existing engine), starter ring gear.

  • EXHAUST – factory  3.6 exhaust WILL NOT bolt in with late 915!  The crossover pipe interferes with the throw out arm.  See below

Q: What exhaust should be used?  Can I use SSIs?  How about a Carrera or 993 exhaust?
A: Depends on how much you want to spend and how much power you want to make.

  • SSIs or early heat exchangers are too small. 1-1/2″ will not flow enough at upper revs.  3.6 came with 1-5/8″ exhausts from the factory, which is on the small side (see dyno numbers).
  • You can use Carrera heat exchangers with 915 but need to replace the exhaust studs and fabricate a muffler.  Carrera exhaust is 1-5/8 and is roughly equivalent to the C2 exhaust but has a less efficient catalyst.  If you ditch the catalyst you can replace it with a muffler.  We generally stock these systems, and they offer decent value with a small performance penalty, but are still superior to the stock 964 exhaust system.
  • You can use the C2 exhaust with a G50 but need to modify the outlet on the muffler.  Still you are throwing 25 HP in the trash can.
  • If you need heat and a 915, then your only high-performance choice is B&B or our headers.
  • You may be able to get the larger SSIs but the muffler won’t clear the engine crossmember.
  • Note: you’ll need their 3.6 headers (1-3/4″) and the muffler exhaust tips need to be modified.  We are a dealer for B&B so if you are going that route, let us know.  Happy to match prices but bear in mind that discounts on B&B are thin.  Personally I can’t stand the resonance of their mufflers so we have a dual-in dual-out which we fabricate in house.  We  used to use their setup but replace the actual muffler.
  • Since 2003 we have our own exhaust systems, either 993 Happy Crab or Instant-G Full Stainless.
    Headers and SuperTrapps are most economical, make the most power, but provide no heat.  We used The Racer’s Group headers and “Georges” headers, and get the Jet Hot coated (see 72 911 project).  Even so they eventually failed, not because of rust or environmental factors, but because mild steel is just not the best with extreme temperatures.  This is why we make our own in house.
  • 993 Exhaust: You can not use the complete 993 exhaust as the mufflers will interfere with the oil tank and rear valance.  On 964 motors you have to rotate the 4-6 cylinder exhaust flanges on the headers, so it’s not much fun.  You can run the headers and catalysts with simple exhaust tips should you so desire but it is a bit on the loud side and you do take a performance hit over headers/B&B because of the smaller diameter (1-5/8″ vs 1-7/8″ or 1-3/4″)  Again, we sell these ready to go.
  • 993 Exhaust on 993 Engines – that works well.  You can modify the catalysts and eliminate the muffler.  The muffler is the famous “Happy Crab.”

Q: What additional parts are recommended?
A: To make the installation easier, we recommend the following options:

  • Cyntex Chips with idle code, $325/$375 with kit:
    • The factory chips have a fuel cut algorithm to bring the car down to idle with the massive dual mass flywheel (40 Lbs).  When the factory chips are used with a lightweight flywheel (as supplied), and especially with a lightweight clutch pack (such as the Sachs Power Kit clutch pack) the engine has a tendency to stall when dropping down to idle.
    • The specially designed Cyntex chips have a special idle deceleration code that eliminates this problem and raises idle to 850 RPM and redline to 6800.
    • Cyntex chips also add 15-20 HP depending on exhaust.
  • Power Steering Housing Block Off $89
    • Obviously the earlier cars do not need the power steering pump.
    • Although the bracket will fit in the engine compartment, it is less than attractive
    • Two options:
      • Cut off the housing (template supplied)
      • Replace it with a block off, which won’t look like a**.
      • When the housing is removed, $27 in seals need to be replaced.
      • We recommend the block off, which eliminates the cam seal and comes with a replacement factory O-ring.
  • 993 Coil Mount on 993 Engines $75
    • clean install, this bracket is welded to the engine crossmember.
  • Evo Motorsports Cone Filter $145-185
    • Looks cool, flows great, lifetime K&N filter, eliminates need to hack up air box.
    • Ours comes with the proper bracket.  If you buy it direct from the manufacturer, you will have to specify parts from several kits, it will cost the same amount, and it is one more vendor to contact and pay shipping from.
  • Single Pulley Alternator Hub Conversion
    • Why?  You’ll notice a little wheel on a pivot on the rear belt called a belt minder (one that runs the fan).  Porsche designed these motors so the alternator would spin faster than the fan because of all the electronic gizmos on the C2/993 motors.  They also designed it so the alternator will spin faster yet on tiptronic cars. This is a problem though.
    • The belt minder is set up to trip a light when the fan belt breaks.  On earlier cars, the alternator light came on warning the driver that the FAN belt had failed.  That’s nice.  Only problem is that with 2 belts, the alternator will continue to charge even if the fan belt breaks, and unless you are willing to set up another warning light on the dash, then you will not know until the motor is cooked!
    • Also – the wheel on the belt minder has a tendency to get noisy and stop spinning as the years go by.  The pivot also has a tendency to freeze up, so that even if the minder is attached to a light, it still won’t come on.
    • The solution is to install a single pulley drive hub.  This will make the alternator light come on should the belt fail, and get around the belt minder issues.  It also has the pleasant effect of spinning the alternator a bit slower so you gain a little power.  Lastly, if you have ever replaced the belts on a 964/993, you know what a pain it is with two to tension with shims.  This makes the whole setup easier.
  • Shroud Blockoff
    • If you are not running heat you should block off the alternator shroud outlet.
    • We make a nice clean inexpensive blockoff plate that comes complete with a distributor vent kit.
  • AC Bracket Delete
    • This is cosmetic, and we have the fixture to perform the modification.
    • You can also do it yourself, but you’ll notice that if you buy the recommended option kit these two mods are nearly free.
    • The finished product is nearly identical to the 993 RS/Cup console
  • Carbon Fiber Heater Tube $200
    • Combine this with a 993 or other exhaust for a clean install.

Q: Will the sheet metal fit or will I need to modify it?
A: There are two items, one modifying the sheet metal so the engine will fit in the car, and modifying the sheet metal so the engine compartment will seal.

  • Included in the price of the kit is modification of the rearmost (nearest the bumper) piece of sheet metal.  Without this modification the engine simply will not fit.
  • Beyond that, the 964 sheet metal fits fairly well, with the exception of the area surrounding the power steering blockoff.  You will need to fabricate this piece.  This is performed for customers on crate motor purchases at no charge.
  • On 993 engines, in addition to the power steering blockoff issue, the sheet metal is too narrow.  Again, if this bothers you then you will need to extend the sheet metal.  We perform this modification on engines installed in-house at an additional charge.

Q: Where do I get an engine, how much will it cost?
A:  Junkyards, private parties or from us.

  • Junk Yards, a.k.a. Recyclers
    • A nice C2 3.6 goes for $9,000 – $11,000.  Used to be they were $7-8K.  Those days are long gone and finding a 25 year old + motor that isn’t leaking is unlikely.
    • Add a bit more for a 993 engine.  Euro 993 no longer available and US Vrams…scarce.
    • VarioRAM motors may be as much as $17K used.
    • A bargain may be a bargain, or it maybe a nightmare.  We have seen both.
    • In general reputable outfits (LA Dismantler, PartsWerks Chicago, DCAutomotive, etc.) sell decent motors with warranties…when they can find them
  • Private parties
    • These can be a joy or a terror.
    • Know your source.
    • We have purchased “Low Miles” engines and had them leak oil, have low compression, etc.
    • Get a description in writing and buy from a reputable source.
  • You can get an engine from us.  It will come with the following:
    • Engine cleaned
    • All conversion parts installed and modifications done
    • Exhaust of choice installed
    • Leak down test performed
    • Valve adjust performed
    • Sensors working (you may THINK this is trivial!)
    • No oil leaks
    • Engine installed and tested in a car AFTER the conversion parts installed.
  • We usually stock one or two engines ready to go of each type.
    • Expect to pay a bit more but expect to get a true bolt in engine that will actually run.
      • We spend 10-15 hours on checkout/tuneup, installation/removal plus parts.
      • This saves an equal amount on your end.  If your time is free it may be less expensive to find your own engine.
  • You can also send us your complete engine.
    • While we can give approximate costs actual cost will be determined when the engine arrives and it’s needs determined.
    • This may not be the most economical.
  • You can have us take care of the whole process. 
    • Drop off your car and we do the conversion.  Period.
    • In general we charge approximately 15 hours for the normal conversion, depending on options.

Q: What about a Mass Flow unit?  Doesn’t that make the 993 engines better?  Shouldn’t I get that?
A: If you have an unlimited budget, go for it.  If not, think twice.

  • Back to back comparisons of 964 and 911 Carrera motors show that the mass flow is worth at most 2-3 HP.  Yes, it’s been tried.  It works, but it is not nearly worth the expense.
  • 993 Engines need to have the rockers backdated if used for prolonged periods at high RPM.  This is enough of a concern that Porsche Motorsports offers a kit for this that includes 911 rockers and special shafts.  It costs about $2000.
  • The Varioram works.  Period.  But the added conversion costs and the “Black Box” nature of the DME make backdating the US engine management system a viable option.
  • Our solution is to use 95/Euro OBD-I management on a 95 motor converted to VRam or on the 96-98 cars.  The engine wiring harness is compatible.

Q: Which Transmission should I use?  Can I use a 915 or do I need a G50
A: We prefer the 915. 

  • For a clutch we use the Sachs Power Kit. 915 is fine up to about 300 HP.  Although the G50 is a stronger box, plan on an additional $4,000-$4,500 if you convert to that as well.  That includes $2000 for G50 and rebuild, $2,000 in conversion parts.
  • A G50 is 100 lbs heavier than a 915.  On an average 911 that’s like reducing the HP by 3-4%.  Remember F=MA?
    The choice is up to preference and budget, but the 915s work well.

Q: Can I use my existing 915 clutch?  How about a “Puck Clutch”?  What is recommended?
A: Yes you can. We advise against it though.

  • If you know about forces and torques, you know that the clutch cares about torque, not power.  The 915 clutch assembly was designed for relatively low torque engines, like the SC and Carrera.  Low power as well with 180-237 HP.  When the factory built race motors, such as the RSR which put out significantly more power, they always used an uprated clutch, like a “puck style” clutch.
  • One would think, OK, I’ll just get a puck style clutch. Bad idea for most applications.  They operate like an ON/OFF switch. These put a high impact load on both the engine and the trans, and is a great way to make the car difficult to drive on the street and ruin your 915.  Also, because they have only 30% of the contact area of a standard clutch, they tend to wear faster.  They are inappropriate for street use.
  • As a solution, SACHS came out with the “Powerkit”.  This clutch solution features a composite/Kevlar segmented (not smooth) surface, a low-mass aluminum pressure plate assembly for quicker revving, and has a higher clamping force on the pressure plate.  The bottom line is that they last longer, don’t slip and have none of the drawbacks of racing clutches.

Q: What about oil cooling?
A: You will need a either two fender mounts or nose front mounted cooler, or a 993 cooler.

  • For street cars a single Carrera cooler with fan or Mocal fender mounted cooler is marginal at best and unacceptable in warm climates or in traffic.
  • The SC cooling loop is not even remotely adequate.
  • The “Brass tube” cooler found in SCs and 1984 Carreras is not adequate. Pricing is around $300 for SC conversions or $850 for a complete system for an early car.
    If the car is to be driven in stop-and-go traffic, it’s a good idea to use a fan on a fender mount cooler.
  • For cars that will be tracked or used in hot climates, we recommend dual Carrera or Mocal fender mounted coolers, or a nose mounted cooler such as Mocal, B&B or Earls.  As with everything else, we can supply this and will certainly match any deal.  We also offer service after the sale (nice when you can’t figure out how to do it!).  We have done pretty much every combination, and you will get everything from the brackets to the fittings to the adapters.  No guesswork.

Q: Can I modify the sheet metal and cross member myself?  Why is this modification important?
A:  Yes, you can do that. Should you is another question!

  • If you do, do not expect assistance since walking you through it on the phone is not much fun for us and defeats part of the purpose of the kit – to remove hassle.
  • The engine cross member should be reinforced.  If you notice rust and/or deformation near the ends it is because the thin material at the ends is beginning to fail (the engineering term is “stress-corrosion-cracking”).  We reinforce this, which is a fairly simple process, but involves fitting metal and welding the whole thing together.

Q: How about Webers, aren’t they the way to go?  Seems a lot easier and less expensive!
A: Not easier, not less expensive, but may offer more top-end power.

  • Upsides and downside below
    • Are they less expensive? Not really.  It ends up costing about $1500 more for carbs IF you can sell the 3.6 induction or purchase a motor without it for $1500 less, so plan on spending about $2,400 MORE to go with carbs.
    • If you use webers or PMOs, you will need 46 mm.  Used they are $1500, new $3,000.  If you get used ones you will need 3 bolt manifolds, $350 now from PMO, so you are looking at $1850.  If you already have webers, you can most likely sell them, so either way, you are out $1850.
    • You will also need a TWIN PLUG spark system.  You cannot run “part” of the motronic for the spark, so a logical twin plug choice is the Electromotive HPV units.  The coil packs and wheel will run you $950, and add another $450 for a pulley, timing sensor holder, and distributor plug so you are looking at $1400, plus $300 for a set of spark plug wires, like from Magnecor, for a total of $1700.
    • This system will then need to be jetted and tuned so you’ll need new venturis, etc. call this $400.
      Total Outlay $3950
    • What do you save, or can you sell?  On a good day you can get $1500 for the intake, fuel injectors, DME, harness, distributor and coils.  You will not need the conversion harness, chips or 3.6 flywheel, or fuel lines, but you will need an early 3.0 flywheel.  Call it $800 savings, so the total is about $2300.  If you think these numbers are off, then recalculate them.  They have to be off by a lot to make up the $1,400!
    • What about ease of installation? I’d say it’s easier to install the 3.6 stock induction.
    • To use the stock system you have to run the DME harness and hang the coil packs, (two hours), hook up the conversion harness (6 wires, an hour) and connect the fuel lines.  On an early car you have to replace the fuel pump and run a few more fuel lines, say 2 hours worst case.  Total of 5 hours.
      On the Weber side, you need to disassemble the entire induction, remove the distributor, mount the webers, run fuel lines, synchronize the linkage, remove the crank pulley, locate the timing sensor, mount the electromotive system, run relays, wire it, replace spark plug wires, etc.  Say 10 hours.  Then you have to tune it!
    • I have personally done this.  See Teala2001.  It took me 4 hours to convert from a 3.4 with Webers to 3.6, and that included R&R on the motor, and 2 days to go to electromotive TEC when I went back to the 3.4.  Absolutely no fun.
    • Will you get more performance?  That is arguable.  Perhaps better throttle response, and maybe a few more horsepower at the top end.  You are likely to lose power in the low end (torque) and part throttle response, cold start, and drivability will suffer. Be prepared to spend time on the Dyno to get the webers right, and expect to retune them on a regular basis.
      What about drivability?  No comparison.  Ever get 27 MPG with carbs?  That is what we got on a recent trip.  We average 22-24MPG, and that is driving the car fairly hard.  The Motronic system starts when it its cold, idles smoothly, and has tons of power.  I’d never switch to webers, but that is your decision.

Q: What about a 915 transmission, will it handle the power?
A:  Yes, as long as it is not abused. We have run over two dozen cars without major issue with the 915.

  • The 915 is good for 300 HP in general,  and is about 100 lbs lighter than the G50.
  • The G50 is generally considered a nicer transmission, and it has few drawbacks other than cost of conversion and weight.
  • The G50 will add 100 lbs and about $7000-$9000 to your project by the time you buy a trans, have it shortened then add pedals, clutch hydraulics and shifter assembly.
  • We recommend the later (75 on) 915 cars with aluminum case and 8:31, though we have run a few cars with the earlier style transmission.
  • Reliability will depend on driving style.  If you plan on drag racing, get a Corvette.  If you are into chirping tires, think again.
  • We have over 4 track years on our 1972 911 with 1984 915, and the trans is still quite happy.
  • If you decide that drag racing is for you, get a Chevy.  915 will  not handle this, nor will a G50.

Q: What about air conditioning?
A: That’s a fair amount of work, difficulty depends on which motor.

  • 911 AC was never anything to write home about, so plan on replacing all hoses to make them R-134a compatible.
  • You must use the 964/993 Compressor in all cases. Neither the S/SC piston type or Carrera rotary type will work because of the intake manifolds. In order to use the 964/993 Compressor  you will need to have the lines made up or adapted.
  • If you are converting to a VarioRAM you MUST remove the deck lid mounted condenser or the deck lid will not close.  The VarioRAM  is simply too tall. You can install an alternative condenser in a tail or in the rear quarter panel.

NOTE:  Please read the FAQ before calling. We are more than happy to answer questions, but it gets old when they are already answered above.