502 in near future, trans question

[choptop]

I will soon be acquiring a 502 that is supposed to put out 650+ horsepower. Its going in my 76 choptop stepside instead of the 427 I was going to put in item. Question is what transmission should I build for it? I have Th350s, TH400s and 700R4s available. I don't think the 700 would live. Im pretty sure I'll have to use the 400 but was curious if anyone has had any luck running a th350 with this much hp/ tq. I know the th350 uses less horsepower which means more power to the ground. It will see most of its life as a ratrod  cruiser but it will probably hit the track occasionally.

[Captkaos]

700R4 if you plan to drive it.

[Edahall]

It kind of depends on the use.  For just track use, a 700R4works well because it has a low 1st gear and doesn't have as much parasitic loss.  However, none of those transmissions you have listed except the TH400 is going to last with that kind of power.  Have you considered the 4L80E?

[LTZ C20]

My I also suggest a "lock-up" torque converter.

[choptop]

This truck is basically gonna be a toy. Im gonna paint it, put a bench seat in it so both my girls can ride, and drive it. It will be beat on pretty good. My right foot isnt gonne behave very well with that much power unless I get to hammer it at the track on occassion. Ill probably go with the 400 because Ive learned that for what I wanna do the loss in horsepower isnt gonna make a difference. As far as the 4L80e, if Im gonna invest in a transmission that expensive, its going in to one of the trucks that will see more highway time than hotrodding. Thanks guys

[VileZambonie]

Go with the 400 unless you can budget for the 4L80E

[Da67goatman]

I drove a 68 impala to prom that my dad's best friend built, runs mid 10s on a built 496 and turbo 350 on cheater slicks.  Hasn't had any problems, except belts keep flying off under heavy accel lol.  I would vote 700r4, but the turbo 350 could work if that's what you wanted.

[heavychevy91]

Are you thinking of stock trans vs stock trans?

[choptop]

Are you thinking of stock trans vs stock trans?

Definitely not. Im a firm believer that all of the components should be built to match, but if itI costs twice as much to build one to get the same benefits as the other, then I don't see the point. That's why I love bigblocks, it takes less $ to build the same horsepower out of a bigblock as it does a smallblock. . I don't think I could build a 650 hp smallblock for the $3k this 502 is gonna cost.

[Engineer]

TH400

[zieg85]

TH400 with maybe a 3.42 gear out back.  With all that torque you will shred the tires and keep decent RPM's while cruising.  Can't beat the torque of a big block...

[roadrage41]

I dunno we put a stock 5.3 in a 454 SS and picked up 2/10th's

[choptop]

the 90 454 SS is one of my favorite trucks, but the 454 it came with was a poor excuse for a bigblock. The 5.3 was an upgrade for sure but a well built bigblock would have been better. just my opinion

[Hollowman]

I actually have an almost identical question. I want to put the GM Performance Ram-Jet 502 in my '80 Suburban.

1. What transmission? I was thinking TH-400, but it's just a guess. I want to cruise mostly in a comfortable way, but still not be too left behind "on the strip". Also, where to buy ready transmission for the engine? I live in Sweden, but will have to import it from overseas anyway I guess.

2. Ford 9"? I heard it's easier to deal with than the equivalent Chevy stuff, any ideas?

Thankful for any good info.

[roadrage41]

Choptop - its getting a 78mm turbonetics front mount setup as we speak.

Hollowman- we had to make some repairs on a Ramjet 502 over the summer, the fuel injection system for that thing is insane. My advice would simply be spend your money elsewhere,  they were designed for boats, leave them in boats. There are many other prepackaged fuel injected big blocks out there. As far as a th400, did your burb not come with one?