putting 454 into chevelle with/TH350

[cheap70chevelle]

I am going to put a 454 into my 70 Chevelle. It currently has a Th350.

Will this bolt right up?

Will the motor blow up the trans?

[Villain281H]

the frame mounts used on small blocks and big blocks in 68-72 models are the same. The TH350 will bolt up to the big block, but I'd probably go with a TH400 behind a big block. Whether the TH350 will survive behind the 454 is dependant on the amount of power/torque the 454 is making and how much the TH350 is built-up.

Derek

[cheap70chevelle]

Thanks for the info.

As far I know, the TH350 is stock. And, I have no idea how much power the 454 is going to put out.

[hsas_69]

Im getting ready to put my rebuilt 454 im my '70 and was wondering if you guys could tell what was the best transmission to put in with it. I would like to keep a four speed manual. Any help would be appreciated.

[hsas_69]

The all stock '70 super sport put out 450 hp, and 500 lb-ft of tourqe.

[e3j1c1]

I would also suggest putting a 400 behind any big block. Weather or not you have posi and how you drive it can play a part in how well that 350 holds up.

If your not sure if your 454 matches your car, consider this: "There were actually several versions of the LS-6 450-hp engine. By specifying aluminum heads, ported valves, and beefy crankshafts secured with four-bolt mains, performance was improved but advertised horsepower remain unaffected."

Stock, Chevelle 454s range from 215HP (1975) to 450HP (1970), depending on the year and model. I would try to find out what year the 454 is that your putting in it if your unsure...or just hook it up to a dyno.

hsas 69: I think they came with a Munci 22, which held up back then, so i would assume it would be a good choice.

[Fyter87]

I would definatly go with a TH400 can handle the power way better. My firend has a 383 with a TH350 and it doesnt get it off the line and the RPM's seem to be higher. He dropped in a TH400 and it really felt like it was a match.

[hsas_69]

The 454 is the original LS6 from the factory but i just had it rebuilt. So a TH400 would be best?

[hsas_69]

It has ported valves, aluminum heads, and the beefy crank.

[e3j1c1]

Yeah, I'd spend the extra money on a 400 if your looking for an auto. I don't think I can vouch for how much "faster" it will make your car as opposed to a 350... but I do know they are tougher.

[68chevelle]

a 400 actualy wont be faster than a 350 becasuse of the first gears they each have. not that its enough of a differeance that anyone would really be able to tell on there own, but its slight. and as far as one being better than the other, it all depends on how each one is set up. persoanly i like the 350's better. no real reason, aside from the fact i like doing things people say cant be done. i had a 350 behind my engine making over 400 pounds of torque. given that it started sliping resently, (it was basicaly stock), so i replaced it with a 200-4r, but while it worked it was the greatest shifting tranny iv ever had, but even that comes down to simply how its set up.

[Tylers Unsure]

put a powerglide in her! no TH400 definately

[hsas_69]

So for a four speed you say a Muncie 22?

[chevyboyy]

ok here goes a th 350 will not last long in almost any 454 even back in the 60's and 70's gm was putting th400 into any engine bigger then about 400 cid and would never put a th350 in any engine bigger then 350 stock in most cases any big block like 396 etc had a th400 in it
so about 99% of 454s made by gm had th400 on them from the factory as the th350 simply couldnt handle the power and tended to break the sun gear every few hundered miles

and yes it would bolt right up but it would break soon after being put toghther

also the 400 would be faster with that 454 and would be able to handle whatever the 454 throws at it all day

[68chevelle]

6 months is a pretty long time to bring something back from the dead. let it die. check the dates please.