70 LS5 into a 72 SS 350

[FirebirdWS62K1]

I have a 72 SS that originally had the 350 in it. Right now there is a mystery 400 in it and a TH400 behind that. Also there is a rebuilt 10 bolt 8.2" rear with Auburn diff, Richmond 4.11's and new axles.

Here is my question.

I have a chance to buy a running 70 LS5 for $800 and when I say running I mean a really strong, recently built motor. Friend of mine bought it and he is a professional mechanic by trade.

What do I need to get the 454 in the car?
Will the bellhouseing on the tranny now work?
The tranny is strong should it be rebuilt?

Or

Should I pull the current 400 and rebuid that, leaving the car useless for the months of rebuild?

Thanks,
Adam

[daverpaver]

First let me say that I am new to this forum and I am very surprised that afetr more than two weeks, nobody has responded to your question. These forums are supposed to be for enthusiasts who want to help each other out. Either people here aren't willing to give advise or they just aren't very knowledgeable. Anyway,

putting a big block into a 72 Chevelle is about as basic as it gets. You will be able to bolt it right up to your Tranny and a T400 tranny is perfect. The radiator hoses should even fit perfectly. Although you may want a four core rad. due to the extra heat of the big block.

I am not so confident about an 8.2 rear holding up to any hard launches. If the tires are able to get traction, then that rear is probably your weak link.

Another thing...the front will drop about 3/4", due to the extra 200 or so lbs. (might be good, if that's the look you want) Also make sure your brakes are up to the task.

Good luck, it should be a real good performer. Although 4.10 is a real low gear for the street.

Dave