1st gen. '79-'85 MAZDA RX-7

frequently asked questions....

...What model 1st gen. RX-7s do you make kits for?
We make conversion parts for 1979 thru 1985 model years. They fit all variations of 1st generation RX-7s, including the S, GS, GSL, and GSL-SE series cars.

...What engines can I use?
Most any small block Chevy engine will work (earlier engines made before '68 generally lack the accessory bosses on the ends of the cylinder heads, which are needed to mount the Mazda PS pump and AC compressor). The carbureted models make for an easier conversion, but TBI (throttle body injected) and TPI (tuned port injected) engines can be used. ZZ4s and LT-1s have also been used.

...Will the Chevy fit under my hood?
Yes, with the proper attention to intake manifold and air cleaner selection. Stock height manifolds and 4bbl carbs require a drop base air cleaner. Higher manifolds such as the Edelbrock PERFORMER RPM require trimming out the inner hood brace in the area of the air cleaner. For TPI engines, the speed density units can be fitted with a throttle body mounted air cleaner, and are much easier to fit than the MAF equipped engines, which require a remote mounted air cleaner.

...Can I use my stock RX-7 transmission?
It's not practical. The stock transmission requires a smaller dia. flywheel than is available for the V-8. This in turn requires the starter to come in from the rear, which in turn requires a reverse rotation starter (very expensive). The stock rotary flywheel has a large counterweight cast into it and is unsuitable for this application. We have brackets that allow using T-350, T-400, 2004-R, 700-R4 automatics, as well as BW T-5 5spd and T-56 6spd manual transmissions (the T-5 shifter location looks like stock). Although a non-overdrive transmission will fit, the overdrive transmissions will greatly improve the fuel economy and make the car much more enjoyable.

...How much weight will be added to my car?
Surprisingly, not as much as you would think. The rotary engine, support equipment, and exhaust systems are heavier than they look. Typical weight gain for a 1st gen car is only 75-125 lbs and a 2nd gen car gains only 125-150 lbs.

...Will my handling be effected?
You Betcha, the way doubling the torque would effect any car. Throttle induced oversteer is much easier, and the added engine compression and displacement require much less casual braking than before. As for the added weight, it's a little less than adding a passenger, and only drops the car 3/4". Stiffer springs are available, but not required. If the car is re-balanced to 50/50 after the conversion, the great handling of the RX-7 is retained. If the car is not rebalanced afterwards, the distribution is still better than the Mustangs and Camaros.

...What about my Power Steering / Air Conditioning?
We make accessory brackets that allow using your stock RX-7 alternator,PS pump, and some stock A/C compressors, with the Chevy. If Both P/S and A/C are required, the A/C compressor must be relocated to the right side of the engine, requiring modified hard lines or specially fabricated hoses.

...Will my stock guages and Tachometer still work?
Yes, they can. We make adapter bushings that allow using your stock Mazda sending units in the Chevy engine, so guage calibration is uneffected. We also have speedometer adapter gearboxes that allow mating the Mazda speedo cable to the Chevy transmission and allow calibration of the speedometer. As for the in-dash tachometer, we offer a recalibration service to restore proper operation.

...Can I use my stock RX-7 radiator?
Some customers have used the stock radiator with success. It still has to be relocated all the way forward to a vertical position for the V-8 conversions. Most air-conditioned conversions require using our HD aluminum radiator. If you do choose to try the stock radiator, plumbing the RX-7's oil cooler into the V-8 will improve your odds of success.

...Do I have to use an electric fan?
No. A 15" mechanical fan will fit and is recommended for use with the Chevy conversions (with the v-8 conversions, there is no room for a fan clutch).

...Will my stock RX-7 rearend blow up?
Probably not. Stock RX-7 rearends are amazingly durable (we recommend using a limited slip differential). We sell rearend upgrades, but recommend using the stock rear first. As a result, we find very few that require the stronger rear.

...What rear gear ratio does my RX-7 have?
Most '79-'85 RX-7s came with a 3.90 ratio. The exception was the GSL-SE models, which came with a 4.08 ratio.

...Is there higher ratio gearsets that will fit in my '79-'85 RX-7s' rearend?
The most desireable ratio for a V-8 conversion, a 3.308, was available in the '82-'84 Diesel powered B2000 / Courier pick-ups. The second most desireable ratio, 3.636, was used in the '79-'82 RWD 626.

...Does my car have limited slip differential?
Pretty much every '79-'85 RX-7 that came with rear disc brakes also came with a limited slip diff.

...Will the added torque twist my car?
The RX-7 is a very sturdy unibody construction. The torque the body sees is limited by the tire size that will fit in the RX-7 wheelwell. As a result, chassis reinforcements are not necessary.

...Will my car be smog legal?
Because we are not performing the conversion, it is up to the installer to make sure all applicable emissions considerations are met. Usually, that means that a same year or newer engine (than the RX-7 chassis) must be used, and that all factory installed smog equipment for the new engine must be functional. Converted cars have passed smog in California.

...How fast will my car be?
Quickness of the car will be greatly improved, as the V-8 torque is about double that of the rotary engine. Overall top speed depends on the transmission selection and the RPM range of the engine. Expect a stock V-8 (with good tires) to produce 13-14 sec. 1/4 mi times.

...What tools will I need?
Only normal hand tools, a hydraulic jack and jack stands, and an engine lift are required. In some cases, an electric drill and bits are needed. An air compressor and air tools will speed things up a bit, but are not required.

...How long will the conversion take?
It depends a lot on the experienceof the person(s) performing the swap. Inexperienced swappers typically require 40-50 hours. Experienced mechanics can do it in 20-30 hours. Additional time should be allowed for installing support systems for EFI engines. Time saving tip: a donor car is recommended for obtaining the engine/transmission (much less time will be spent tracking down misc. parts).

...Are there any special requirememts?
A small dia. (pre '75/post'88 or aftermarket) distributor is recommended. The larger dia. "HEI" units require massaging of the firewall for clearance.
A "short" water pump (pre-'68) and pulley set is required. Double groove crankshaft and water pump pulleys are required to drive the P/S pump and/or the A/C compressor.
A new driveline or driveline modifications are required. Driveline modifications done locally are usually cheaper (used parts and no shipping), but we make new shafts using new parts if you need one.
A trip to the Muffler shop is usually called for to hook up the exhaust.

1st GEN. V-8 BASIC KIT for T-5 transmission