Tranny Help
 

My truck originally had an inline 6 and th-350. I am putting in a 475 horse 383 and wanted some advice on wheather or not I should put in a B&M th-400 from Summit or just get the 350 beefed up from a local shop. Also I wanted to know if the 400 will only fit with a high hump cab.
Thanks in advance
Manny

I may be wrong but,I think that you should not need a high hump for your 400 tranny.Also,by all means,GO WITH THE B&M shifter!!

I think it was TXFirefighter that said the low hump will work fine with a Th400 as long as the cab mounts are in decent shape and not compressed too much.

the Th400 never needed the high hump, that is for 4x4's, 4 speeds, and big block trucks...and V-6 1/2 ton automatic trucks on the GMC side of the house.


Personally, I like the TH350...I would stick with it.

Are there any pro's and con's one vs. the other? I've heard that the 400 was built stronger and would last longer. That was basically the only reason I was thinking of swapping.

It is stronger, and will likely last longer.

Personally, I'd just beef the TH350 a bit and run it. It's a great transmission, and besides, you already have one.

You can easily run a Turbo 400 under a low hump cab as long as you have pretty decent cab mounts. On my 70, when I did a swap like this, the cab hit the trans case. After replacing the 34 year old mounts, it cleared by a good bit. You'd be suprised how far these old trucks sag when they age.

I have a th400 in my 67 gmc with the motor(350) in the six cylinder position (rear) and it clears by quite a bit. It would have a lot of clearance if it were in the correct location.

It takes more horsepower to turn a th400, I ran a th350 in my 6:71 blown 350 for 8 years on my 1930 Model A Ford (powered by Chevy) :metal: