phone: 360-391-1208

...Welcome to the original home of the V-8 powered Mazda RX-7, where we've made V8 conversion parts for the RX-7 for over 20 years. Since our 1st RX-7 / V-8 Kit sale back in the early 90's, we have sold thousands worldwide with customers in Argentina, Australia, Brazil, Canada, Dutch Caribbean, Fiji, Germany, Greece, Guatemala, Japan, Luxembourg, New Zealand, Pakistan, Portugal, Puerto Rico, Trinidad, United Kingdom, Virgin Islands, and thousands more customers right here in the USA.

...Installing a V-8 into an RX-7 is a surprisingly easy engine swap. Although our instruction guides may seem a bit long, don't be intimidated- the swap is actually quite straightforward. Most people would agree that installing a V-8 is probably easier than re-installing the rotary engine. Most hotrodder types are able to complete the mechanical part of this swap with little or no direction at all. We have had people start their conversion on friday, and be able to drive their car to the exhaust shop on Monday.

...The RX-7's layout and structure is well suited to engine conversions. The rotary engine's eccentric shaft centerline is way up in the center of the rotary engine, dictating a much higher transmission location than that of a piston engine. The net result is that Mazda designed the RX-7 with a HUGE transmission tunnel, big enough to fit even the monster T-56 6 spd manual transmission which was used in the Viper and Corvette. The rotary engine's low torque output required Mazda to use a very heavy flywheel and a high rear gear ratio, a combination of factors that combined induce large amounts of stress on the RX-7's rear axles and hubs. Mazda planned accordingly, and designed plenty of strength into the RX-7's rear differential/axles/and hubs. Experience has shown that the stock NA RX-7 components are strong enough to withstand low 10sec 1/4mi passes, a feat that requires around 500hp.

About 1/2 way down this page you will find links to pages containing specific info, on-line instructions, and parts lists / pricing.
Be sure to check out our RX-7 Conversion Index, a page of links to pictures of various RX-7 conversion projects. Please e-mail us if you have one you would like to add.

...Think the v-8 will forever ruin your handling? The August 2005 issue of Grassroots Motorsports Magazine featured quite a few V-8 powered RX-7s that entered their $2005 Challenge event in Florida. The premise of the event was to build the best handling, best appearing, and quickest car possible for a total budget of $2005., including the price of the car and all components. You will be surprised at the wide variety of entrants and how creative they are. Check out the August 2005 issue for a feature on this year's challenge winner, a FORD POWERED 2nd gen RX-7!!! For a free copy of the magazine or to check out the $2005 challenge results, go to the Grassroots Motorsports website.
In the 2004 event, of a total of 76 cars that participated, a total of 9 RX-7s took part in the event, 5 V-8 powered and 4 rotary powered. In the drag race portion, all the V-8 RX-7s finished ahead of the rotary powered cars. No surprise here. The quickest V-8 RX-7 recorded a 12.636 ET, the quickest rotary's ET was a 14.323. What DID suprise a lot of sports car people is the results of the autocross competition. The quickest RX-7, a V-8, finished nearly 4 seconds ahead of the quickest rotary version. Among the 9 RX-7s present in the autocross, V-8 power captured 4 of the top 5 spots. Don't listen to those who tell you that a big V-8 will ruin your handling!!!
Daryl Evans's ZZ4 powered RX-7 solo car was 2005's local, regional and Canadian Western Champion in E Mod.

Be sure to check out Granny's rotary powered.....4 rotor Outlaw Dirt Racer.

...If you would like to jump to the specific pages for the 1st, 2nd, or 3rd gen RX-7 / V-8 conversion parts and current prices, click on an image below...

1st gen '79-'85 RX-7 Conversion Parts & Info

2nd gen '86-'91 RX-7 Conversion Parts & Info

3rd gen '93-'95 RX-7 Conversion Parts & Info


...Since we are not performing the conversions, it's up to the installer to insure that all applicable emissions considerations are met. This usually means that the new engine must be of the same or newer year than the car, and has all the engine's systems complete and intact. The exception is usually the catalytic converter, and that system usually has to be consistant with the requirements of the chassis. There is no room for an air pump with these conversions (some Chevrolet cars came with ELECTRIC air pumps that can be remotely mounted).

...The RX-7 chassis is well suited to V-8 power. It was designed as Mazda's flagship sports car right from the beginning, with many features that address the dreaded chassis flex that plagues other small car V-8 conversion candidates. RX-7 design features include...
1...a very large transmission tunnel. The large tunnel dimensions necessary to accomodate the rotary engine's higher transmission location add considerably to the beam and torsional strength of the RX-7's floor pan. The 3rd gen cars use struts across the bottom of the tunnel to further enhance this effect.
2...deep door sills add even more beam strength.
3...generously rounded door openings add body structure torsional strength.
4...subframe connectors are installed right from the factory. As countless highly abused RX-7's can attest, there is none of the buckled quarter panels or popped out windshields the are common with other V-8 converted small cars that were originally designed with economy in mind.

...The stock RX-7 rear axles are amazingly durable (internally, the parts are similar in size and even stronger than the Chevy 10 bolt that comes in the '90s Z-28). While we offer bolt-in narrowed rear housings and axles for the 1st gen. cars, unless you are REALLY going to abuse it, we suggest you try the stock rear first. There are many V-8 powered 2nd gen RX-7s on slicks running mid-10 sec 1/4 mi times on the stock rear, a feat that requires 475-500hp. The clutch type limited slip up thru '88 is very strong 4 pinion style much like the diff design used in the Dana 60. Although it may be hard to believe, the rotary powered RX-7 drag racers are probably harder on the rear than the V-8 powered guys. The reasoning behind this is that most all rotary powered RX-7 drag racers use a manual transmission, a metallic clutch, and a heavy flywheel spinning at 9-10K rpm to assist the low torque rotary in launching the car. An incredible amount of stored energy is released into the rotary drivetrain to launch the car, enough to launch the car well even if the rotary engine died on the line. In the case of the V-8, plenty of torque is on tap to allow low rpm starts, also making it much easier to modulate the power to make the most of available traction.

...Here is a list of the rear axle gear ratios that came stock in the RX-7...

'79-'83 ALL.............................3.909
'84-'85 ALL (except GSL-SE).............3.933
'84 GSL-SE..............................4.083
'85 GSL-SE..............................4.077
'86-'91 ALL (except automatic)..........4.100
'86-'91 automatic (except convertible)..3.909
'88-'91 convertible.....................4.100
'87-'91 Turbo II / GTU..................4.100
'89-'90 GTUs (T-II rear)................4.300
'93-'95 w/ manual trans.................4.100
'93-'95 w/ automatic trans..............3.900

...The 1st gen RX-7s all used a 7" dia. ring gear.
Cars with rear wheel disc brakes, such as the GSL-SE, all came with a limited slip differential.
The '84-'85 cars used larger diameter axles, and have a larger spline in the differential side gears.
The axle side gears can be swapped, allowing the different axle diameters to be mixed and matched.
Higher gear ratios for the 1st gen cars are available, a 3.683 ratio (came in the '79-'82 RWD 626, and is available new), and a 3.308 ratio (came in the '82-'84 diesel powered Ford Courier and Mazda B-2000 pickups, not available new anymore).
The '79-'85 12A cars all had a 4 on 110mm wheel lug pattern (hard to get wheels for, but only 1mm off from the 4 lug FOX Mustang).
The '84-'85 13B powered GSL-SE cars had a 4 on 4-1/2" wheel lug pattern (same as older '60's 4 lug Ford Mustangs, etc).

...The 2nd gen RX-7s used a 7" ring gear as well (with the exception of the Turbo II and GTUs cars, which used a larger 8" dia. version), but have a unique long pinion shaft (not interchangeable with the 1st gen RX-7 gearsets).
The GXL cars from '86-'88 came standard with a clutch type limited slip differential. As an option, '89-'91 GXL was available with a viscous limited slip. While the Turbo II came with the clutch type limited slip, the GTUs cars should have a viscous limited slip diff as standard equipment.
The 3.90 ratio from the automatic cars is the highest ratio available for IRS 2nd gen RX-7 rear.
The 2nd gen cars were available with 2 different wheel lug patterns.
The Base models came with a 4 on 4-1/2" pattern (same as old '60's 4 lug Mustang).
The GXL, GTU, and Turbo II all came with a 5 on 4-1/2" lug pattern, also shared with many 5 lug Ford & Mopar applications.
The S4 '86-'88 5 lug cars also come with larger brakes, and 4 piston calipers. The S5 '89-'91 base models got 5 lug, but came with the smaller single piston brakes.

...The 3rd gen RX-7s use an 8" dia ring gear.
The automatic transmission cars all use a 3.90 gear ratio. The manual transmission versions use a 4.10 ratio.
The automatic equipped '93-'95 RX-7 used a larger 4.120" dia diff flange bolt pattern, same as a T-II. The manual trans '93-'95 RX-7 had a smaller 3.786" dia diff flange bolt pattern, same as the NA 2nd gen '86-'91 RX-7. Both use the same pilot dia on the pinion flange, only the bolt pattern is different.
All the 3rd gen RX-7s have a 5 on 4-1/2" lug pattern, but the offset is different than that used on the 2nd gen cars.

...Keep in mind that what makes an RX-7 both fun to drive and fast, is it's very good power to weight ratio. If you add 75-125 lbs but back it up with 100-150 horsepower, you've actually IMPROVED the P/W ratio by a LOT!!!


Here are some weights for some of the various 2nd gen RX-7s in stock form:

The base models and factory lightweights weighed about 2700lbs.
The automatic equipped cars were heavier at 2735lbs.
The Turbo II cars were much heavier at 2850lbs.

(these weights come from Mazda factory sources, and obviously do not include the driver)

Here are some actual scale results from a recent 2nd gen Chevy V-8 ZZ4/Tremec 5spd conversion, before balancing:
.....3000 lbs = Total Weight (including 210lb driver, 1/4 tank of fuel)
.....1580 lbs = Front
.....1420 lbs = Rear
This car, which did not have A/C or P/S, will balance by just filling up the fuel tank !!!
Given the ZZ4 crate engine's factory horsepower rating, you get a 8.11 lb/hp ratio, BETTER P/W RATIO THAN A $31k 2014 MUSTANG GT !!!
Not bad for a car you can duplicate for under $10,000, including a BRAND NEW crate engine.

If you opt for SB Ford V-8 power, the weight is even less. A typical Ford powered 2nd gen will weigh in at around 2750 to 2800lbs.

...Wiring Info Pages For 2nd & 3rd Gen LS1 Conversions...
The wiring info pages make wiring your LS1 conversion easier than ever. The format eliminates the confusion that comes from having multiple descriptions of the same circuits. The focus is on specific connections in specific places, without the tech background info that can take quite a bit of time to digest.
2nd gen LS1 wiring info
3rd gen LS1 wiring info

...Ford V8 Powered RX-7 ($1932. total cost) Featured In November '05 Issue of Grassroots Motorsports...
Built by Jeremy Butts and Mark Kleckner, this is a feature article on their car (complete w/ a detailed budget sheet) that won the Grassroots Motorsports $2005 Challenge. Not only was this car built for under $2000, it also ran a 11.676 et in the 1/4mi. It's a great looking car as well, as it also won the concours portion of the competition. Be sure to pick up your copy of Grassroots Motorsports today. Can't find it on the news stand? go to their website for a free copy.

...Economy Versions of our FD/V8 Conversion Parts Available...
Designed with value in mind, these "econo" spec parts will help put a V8 powered FD within the reach of a guy on a budget. Options for SBC, LT1, LS1 engine locations and steering rack (power or manual) position for those that must fit the engine under the stock FD hood. CLICK HERE to find out more.

...Speedometer Calibration Info Page...
We added a page to take all the guesswork out of re-calibrating RX-7 speedometer correctly for your V-8 or V-6 conversion. Now it is possible to select and install the correct drive and driven gears for your specific application while it's easy- before the transmission is installed in your RX-7. CLICK HERE to go to the speedo page.

...V-8 powered RX-7's sighted in Hot Rod Magazine...
The Sept 2005 issue of Hot Rod includes pics of 2 V-8 powered RX-7's. One entered the Hot Rod "Top Speed Challenge" and the other Hot Rod's "Pump Gas Drags"...
...The Top Speed Challenge entry of Frank & Larry Waddell captured the "Real Street" catagory with a 154mph "all motor" run that ended early with an exploded clutch. The 358 Chevy powered 2nd gen RX-7 is equipped w/ a Predator carb, T-56 trans, and a stock RX-7 rear. Hot Rod noted that the car has been clocked as fast as 202.702mph on nitrous.

...3rd gen '93-'95 RX-7 Lower Control Arm Pivot Box set... If you are either looking to build your own custom subframe from scratch or want to avoid the hassle of finding an FD subframe to send in for a 20b conversion core, this pivot box set can make your life a lot easier. Complete with eccentric stops and lightening holes, these will help your project avoid that "hacked stock subframe" look. We make these from 12ga sheet, same as the stock Mazda subframe, and build in an extra .020 width to allow for the extra thickness of a powdercoat finish, insuring ease of assembly and proper fit of the suspension bushings. The entire set weighs less than 6-1/2lbs. These are the same parts we use to fabricate our own 3rd gen subframe. Pricing for the 4 pc set is $395. + shipping. CLICK HERE to go to our 3rd gen conversion page, where you can find additional info and pictures of these parts.

...Did you know we make Basic Kits for RHD RX-7's?...
...We've been selling them for quite some time, but never bothered to add them to the site.
...The 1st gen RX-7 Chevy and Ford Basic Kits fit either LHD or RHD cars.
...The 2nd gen RX-7 Basic Kits are available in the USA style LHD version, and also a Japan / Australia / European style RHD "mirror image" version.
...Both LHD and RHD Basic Kits are the same price.

NOTE: Since we are not performing your conversion, it's up to the installer to insure that all applicable emissions and legal considerations are met. This usually means that the new engine must be of the same or newer year than the car, and has all the engine's systems complete and intact. The exception is usually the catalytic converter, and that system usually has to be consistant with the requirements of the chassis. The engine will also likely be required to be from the same class of vehicle (example: no engines from heavy duty trucks installed into passenger cars).
Before proceeding, be sure to consult the appropriate local authority on the legality and conditions necessary for a successful and legal engine conversion in your area.

If you would like more info on completing a smog legal conversion in California, CLICK HERE

Under Jamie Butler's hood- 9.84@136mph with small tubes and NO nos

....some feedback from our customers....

From Pedro in Florida...

Turbo stroked (331) R302 block, Aluminum heads, ac and power steering. Dynoed at 998hp 1180ft/lb torque at a conservative 18 psi on pump gas (24 degree timing). Stand alone fuel injection with distributorless ignition, 1000 cc injectors, Dual fuel pump system, CK Performance Stage 2 AOD, Ford IRS 8.8 w/ 2.73 gears and custom axles.

Amazingly, the stock non-turbo rear end put up with the punishment from the engine. I have never put slicks on the car, but i am running 275/18/40 tires. The tires spin, however once they do grab the car pulls hard and the rear/axles did not give. I have raced Suzuki Hayabusas and kill them from a 50-60 mile roll and the rear had absolutely no noise and virtually no backlash. Mazda did an awesome job on the rear, but I have switched rears because of gearing issues.

I have switched from a 5 speed to an automatic. Overdrive (4th) on the AOD is limited to only 550ft/lb of torque, so a lower gear was required for the 1.1 ratio 3rd gear.

Another factor of power to this car is that there are no signs of body flexing what so ever, maybe all will change once drag radials go in. Again thanks for your products , my toy could not be complete without your support.

Thanks for a great product,

A note from Tony in FL...

Hey Grant...
Its been awhile since I got a set of your headers. I'd liked to have sent you an 8 second pass, but the year came to a end with a 9.04@148.66.

Having wheelie problems now!

The new season has opened in Florida, and Tony has his 8 sec run...
Time to install a parachute!!!

Congratulations Tony!

From FIJI...

Dear Sir,
We wish to do our second project of installing a Ford 351 Cleveland into a Series 2 Mazda RX7.
Our first project of installing Chevy 350 using your kit went very well.
The car is doing 10.88sec in 1/4 mile.

We now wish to install Ford 351 Cleveland into Series 2 Mazda RX7 using your kit.
Could you please advise me the cost and availability?

Tauz Khan
Laucala Beach Estate

Here's some pics from Tauz-
note that this car is RHD...

Just want to share my rx7 pictures with you ,since your subframe made my dream car reliable again.


I did notice that you had a picture on your website already, thanks its looks awesome.

Rosendo Dimas
San Antonio,Tx

Below is a pic of Rosendo's Blower equipped / Chevy powered 3rd gen RX-7.

Hey Grant,
It's Brad with the 5.0L Ford EFI 1st Gen conversion. I've put 35,000 trouble free miles on my swap and just changed to a new low budget radiator that works out really well-- a mid 80's Volvo 240 ( I crashed the other into a parking bump). It fits the chassis perfect, easy to mount, and has sufficient cooling for the Ford V-8, even in 90 degree heat (need to trim out the hood secondary panel slightly). Thought this might be helpful. My V-8 swap, with your help, is the most enjoyable auto project I've ever done!

Brad Bergholdt
Evergreen Valley College

To see more of Brad's smog legal Calif conversion, Click Here

Hi Guys,
Just wanted to thank you guys for the info i gained here and the parts i got from you to complete the neatest car i have ever owned. I put a 302 with AFR heads in a 85 rx7. Much to my delight it went 11.81 @118mph last night,,, stock rx7 rear with radial tires,, not nittos or drag radials,, but generic performance tires. Im so happy i could shit!!! LOL It weighs 2550 with me in it. It pulled a 1.74 60 foot just easing it off the line, no nitrous or blower, all motor, this car is gonna be a blast!!!! If i send you some picures would you put it on your site??? Im still in the process of getting ready to do the body and paint,, and an 8.8 rear is planned real soon. Also do you know what the easiest way to change the lug pattern would be???


After this, Ben went kinda he's doing low 8.0's @180mph!


I bought your basic kit 3 years ago and love it.
With the mild sbc I built for this car it runs 11.0 all day.
I have about 250 passes on the car since I built it.
Thanks for building a good kit for me to start with.

Steve Marco
ps- sent a pic of my car I would like to see it on your site. Thanks again

Hi Grannys-
I recently did a swap with your kit, on a 90 turbo rx7. Turbo 350 trans, and Chevy 350 crate motor (330 hp). The conversion went well, and I love the car. At the track, however, i'm running out of gear.

My car ran 12.56@106mph with no NOS. That was great. But add 150hp NOS kit, and WOW, it ran 11.33@112mph. Thats impressive, considering that I shut the NOS down at the 990" mark because it was bouncing off the rev limiter (set at 6800 rpm).

You see the problem, I need more gear. I'm not to sure what the stock rear is, but I think it's 4:10. I need like 3:73 or 3:90 that should solve my problem.
Any insight whould be great.


Blackwood, NJ

UPDATE:..."I posted earler that my rx7 was running out of gear and was toying at the idea of using a 700r4. It worked great i was running 11.30s with a t350 trans using 150 shot of nos. Since then ive run 10.80 @128 still with 150 shot on a stock 350 330hp crate motor. Not bad!!!

UPDATE #2:...just thought everyone should know Frank's car has turned a best 1/4mi ET of 9.32 on the stock RX-7 rear (including stock axles!!!) on 26x8 slicks...he's even got a 9.50 run on video.
Thanks to Grannys for the help along the way with questions i had."

UPDATE #3:...GRANT, Heres a pic of our car from the chassis shop!
We were runnig 9.32 @ over 150mph and got thrown out of all the local tracks. We decided to go to a safer setup. Our car is now 3/4 tube chassis and 700 pounds lighter! We are still running you motor mount kit which held up to hundreds of 9 sec passes with out any problems.
We are still running the same headers and motormount kit in the tube chassis car.(If it ant broke don fix it!) Thanks again, I only wish your rear kit was ready before i shipped our car out to the chassis shop. I sure we would of run in the 8s with a Power glide and your rear set up.

Frank Deninno
Auto Addictions Inc.
New jersey

...Misc Instructions and Information...

On-line Install Guides for RX-7 V8 Conversions
Step-by-step guide thru the conversion process
Includes LSx engines specific electrical modification details

V-6 / V-8 Tach Re-Cal
An easy to follow guide on how to make that RX-7 tach read correctly

RX-7 Speedometer Re-Cal Info
Easy to follow information to choose the correct speedometer drive and driven gears
for your specific combination of tire size and rear gear ratio

RX-7 weight specifications and
how to keep your perfect 50/50 weight distribution
(it's not as hard as you might think)

RX-7 Tech Triva
Hard-to-find tech specifications
You may find something useful in here

2nd gen RX-7 Chassis Print
Includes critical dimensions for crash damage accessment and repair

RX-7 Conversion Index
Click here for a list of links to 40+ V-6 and V-8 converted RX-7s

9sec club
Some quick pics of the V-8 powered RX-7 street cars in the 9sec club.

Ordering Information

Parts, Prices, General Info
Conversion Package Info

Click Here for Ordering Information

...If you have any questions for us, feel free to e-mail or call us at 360-391-1208

...Our mailing address is:
Granny's Speed Shop
POB 814
Concrete, WA 98237

A Borg Warner T-5 5spd from a '92 Camaro
installed in a Chevy V-8 powered '79 RX-7

Here's an ad from the '90s, too bad the prices are no longer effective...