Fairly new SA first gen owner here, (new to the forums as well, but figured I'd sign up considering the thousands of dumb questions these have helped me answer over the years) just wondering if anyone has any idea on what sort of power the frame/chassis are good for. I believe my car is an S model (no sunroof, peasant spec features, etc.)

I have a pretty tame 350 sbc build that might make 300hp if you turn the A/C off and pray, and upper 300's torque

Ford 8.8 rear end and a t5 that both seem to hold up just fine and should continue to, but my main concern is the overall chassis flex that I get at peak power in 1st and 2nd. I know this is partly due to my mostly stock suspension and steering that doesn't really feel attached to the road (or in the case of the suspension, a little TOO attached to the road) but I can feel the car flexing under the torque. Has a little bit of minor surface rust underneath but definitely not enough to be structurally compromised.

Does anyone have an idea as to what the frame of these things can take reliably, and what would be my best road for reinforcement? My motor mounts are definitely solid. It won't be beaten on too hard but I want to know that I'm not going to flex the chassis into a pretzel over time. Anything helps

Cheers


Engine build, if it matters:
4 bolt main 350 bored .30 over
comp xtreme energy 268 cam
edelbrock 600 carb
shorty headers
vortec heads

 

Once I would flip you crap for the v8… In the current year of our lord, if you can keep it on the road , good for you.

the SA chassis is pretty stout. Assuming no rust compromises. In my years I can’t say I ever heard about twisted chassis.

 

I have similar setup. Supposedly they are very stout due to the transmission tunnel. Mine also has factory supports where the bins go behind the seats. No idea what the limit is, but I don’t think you have anything to worry about. Subd to find out.

 

the Rx7 is way stiffer than the car the engine, and trans and diff came from....

 

Yeah after looking through some stuff I think front/rear sways and some stiffer suspension should sort it out, mostly. Are you also on an 8.8 rear?

 

nah. Went with an 84 I think gsl rear. The one with 3,909 gears, disc and lsd

edit: it does have moser axles in it though. Luckily I have my 1980 chunk and extra ring and pinion, although I think the 1980 pinion would need some massaging to fit if I ever have to find out. I would do the 8.8 if I had to do it over again. For strength and lower gearing etc.

figure that tranny will only hold about what the rear end might lol

 

Yeah that would be a gsl rear, they had rear discs. Seems like that's the other option for higher power as opposed to a ford 8.8 or 9. Probably would be a bit lighter, but also tough to find nowadays

 

I've seen lots of naked Fox Mustangs and 3rd Gen Camaros and the RX7 is built allot better.