302 into an FB
 

Good Afternoon. My name is ROb, I'm a new guy from Ontario, Canada. I have always been an RX7 fan. I am doing a 302 Convertion over the winter had had some questions.


ANyone on here done this? I'm doing one as my winter project and needed some more details. I tried to e-mail Grannys but the email got bounced back.

Did you use the Grannys kit?

Difficulty of install, it seems pretty straight forward. ANy other tips and pointers would be great thanks guys.


Thanks in advance. :bigok:

search for it... use the search buttom at the top of the page

No, don't do it. Keep the rotary in, come on man. Anyways, welcome to the forum. It's your car so do what you want, but the rotary is so often. First do some research about it. Use the search button and check out the faq page at the top of the page. Post some pics of your car when you can.

If you are set on the conversion, there is a seperate section on the forum for this. https://www.rx7club.com/other-engine-conversions-non-v-8-118/

Thank you. Any help is appreciated.

dont listen to the haters, if you want to do it, do it. but youll probably get more information if you go to the other section, there is one specifically for engine swaps. https://www.rx7club.com/forumdisplay.php?f=118

EDIT: im slow...

I'm not a hater, i just love the rotary. Plus, i said he can do what he wants

yea, i wasnt necesarilly directed at you, but in know like 50 other people are going to come in here and call him stupid for doing it. and i honestly dont think its that bad of an idea, id like to do one myself some day. i mean, i know how one could get fed up, being on like your 3rd rebuild of the rotary...

As you could probably already tell, there isn't much love for the piston swappers in the first gen section. Regardless, welcome to the club.

My 84' 5.0 GSL-SE
 

Granny's kit is over priced. I built mine for about $10 worth of steel stock from Home Depot. The key is to use a 5.0 not a 302, or at least 5.0 valve covers, oil pan, and stock headers. I shoot you the engineering drawins if you want to build your own. As for the weight, with an aluminum radiator, intake, & water pump and a full interior from an 81' GSL mine weighs 2,550lbs. And that's with a heavy ass AOD tranny. Use a T-5 and you can shave about 100lbs off that.

And for all you rotary lovers, don't worry my 12a is headed into a 71' MG Midget. 150hp in 1200lbs.

Well, to tell you the truth, if I were to do it all over again from the start with my car, I would just have thrown a late 80's mustang 5.0L converted to carb in my car. Would have spent a LOT less money. I've got about $2000 into rotary engines, and I could have swapped a 5.0L for probably $1000.

I would recommend the 302 fb swap, i found a warmed over older 351w motor at a very low price and used that with granny's kit, but if I were to do it over I would definatly use a 86-92 5.0L HO motor. There is so much aftermarket support at such a low cost these days that you can't beat it. the tv show pinks is a perfect example 75% of the participants race mustangs.

anyways going carbed with a 5.0 ho can make good power with a simple $400 plate kit, but be aware even the best stock 302 based block can crack at as low as 450rwhp.

Sure, the block can crack at that low a hp, but all things considered, your putting the engine into a 2400 lb car. 350hp is enough to put you in the mid 12's, assuming you can put the power down to the ground.

I have a friend that made an est. 300hp out of an 86 5.0L. He put it into an 83 Mercury Capri, but its was just a few aftermarket parts he put into it. I think it was just a "mild" cam, edelbrock carb and intake, headers and a very free flowing exhaust.

Halo rob, welcome to teh forusm.

2500lbs + 450rwhp (V8 early torque delivery) = mid 11s with race rubber. That is faster than the new Z06.

Well, the point of using a V8 IMO is to keep things cheaper than using a rotary to make the power. Once you go this fast, you NEED a roll cage to run at the track. Not only that, the thing would just be plain scary on the road. One wrong touch on the gas pedal and your going sideways. Its one thing to have 450hp with little high end torque, but its another to have 450hp with a ton of low end torque.

If you have that power you should have the suspension sorted to handle it, in which case you should be able to tune handling into the equation, fast cars are only scary if they are done half assed or the driver is a half-wit.

The point of swapping a V8 into a rotary isn't cheap power, it is to have power that lasts, that doesn't need 5 additional gages to safeguard, that doesn't become annulled on the first bad tank of 91 octane gas, that doesn't cease to exist if you run the car out of gas, that doesn't require smog illegality, etc. etc..................

It's always easy to think that we're only doing it because it is cheap. Any rotary-phile could have taken the $4k I put into my swap and dumped that into a turbo rotary that would match and probably exceed the power output of my V8, but would that make a car that could be driven every day to work and back, need only fluid and filter changes to keep running, and pass the smog visual in any major city?

The V8 Explorer motor would be a good choice. Short water pump & acc. for clearance, Rear sump oil pan, Cobra style GT40 upper & lower intakes, 65mm Throttle body, engine oil cooler, GT40 heads (mid 1990s) GT40P heads to 2002.

Change fuel injection to carb. W/ E303 cam & you've got a 270 horse power crate motor for about $1000. Upgrade to a good set of alum. cyl. heads (save 50lbs.) & B303 or better cam. you'll be in the mid 300 HP range.

You can pick up these motors at the salvage yard for about $500 or on Ebay for even less.

The other boys are right. Power is'nt everthing.

Good luck with your project

This is the key point in making big power with the small block Ford.
For comparison and insight:
LSx Aluminum bare block weight: 108 pounds
LSx Iron bare block weight: ~195 pounds
Stock 302 Iron bare block weight: ~130 pounds
DART 302 Iron bare clock weight: 160 pounds

30 pounds of webbing and reinforcement is a lot of material to put back into a block and the main reason stock 302 blocks tend to split in half above 500whp.

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Yeow! The 302 block weighs 130 pounds! I don't know how I lifted mine off the floor, carried it 50 ft. and put it in the trunk of my car one day. An assembled rotary short block seemed heavier when I l picked one up and put it onto a table a long time ago.

For reference, that 130 pounds is roughly the amount of weight added to the front of the car after swapping in said 302 w/ aluminum heads vs. turbo rotary. Some skinny guy could lift that shit.

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Motor mouts pic
 

I'll have to get the engineering drawings from my home computer tonight, I don't have access to them here at work.

Hey. That's MY hand and My ruler.

Has someone actually weighed a 302 with accessories vs a 12a with accessories

Has anyone weighed a fully dressed lawnmower engine vs a fulley dressed chainsaw engine?