I'm in the process of having a 400sbc dropped into my 85 firebird (originally 305). Will the manual 5spd transmission that is currently in the car hold up to the torque from the 400?

 

If you dont beat on it itll last you long enough to get a t-56 or something stronger


thats a t-5 there RLY weak

 

It won't last long, even under normal use.

That's from a 90 bird with factory 305 tbi, converted to 400.

Also, it's too tempting not to get on it every ONCE in a while...

"DEAD TRANNY WALKING; DEAD TRANNY WALKING...,"

 

It is shock more than torque that kills them. A long-time member reports having a healthy 400 in front of a non-WC T5 that lived for many years and miles, because he knew how to drive it and not do clutch dumps or try to speed shift it. If you want to beat on it, do the T56 (or Tremec, or something much stronger) or go auto.

 

It won't hold long if you floor it alot.When I went from the stock L69 with about 80,000 miles to a zz4 I blew the tranny up the second time I floored it!!! I would also start saving for a new rear if this 400 has any *****!!! Thank god for GN's and their 8.5 rears. So much cheaper than building a 12bolt or 9 inch.

 

You don't blow up 8.5's?

What am I doing wrong? heheh Heavy right foot, I guess...

I guess I like heavier stuff...

 

8.5 rears are way stronger then a 7.5. I have seen guys with 400+ cube small blocks run them in the 11s with the stock 8.5 with over a 100 passes and no breakage. The ring gear is almost as big as a 12 bolt.

 

8.5 is.. well... an 8.5" ring gear. The 12-bolt uses a 8.875" ring gear. The 8.5 10-bolts are just about as strong as the 12 bolt is because of that.