sm block to bg block swap

[Nasty_Nate]

I just aquired a 427 BB for my 83 k-10, and I was wondering about the motor mounts. It currently has a 350 sb, and was wondering if the mounts were the same. I'm also planning on putting a th400 inplace of the th350.

Any info as to the swap would be cool.

nasty

[cherryelky305]

The mounts are different, mounts from a BB 400 should work, and the th400 is longer so you need to work on your x-member

[Nasty_Nate]

what about using the mounts from the 427? I believe I can still get ahold of those. Are you saying I should get both halves, frame and block mounts, or just the ones from the frame. Also, I've already made plans to relocate the crossmember due to the 203/205 transfer case combo i'm using.

[cherryelky305]

There are usually two kinds of mounts, tall and short.

I havent actually worked on a bb but you might be able to get away with the mounts on the engine side and then use the small block frame mounts. I dont know if you can mount them together.

Sorry I couldent be of more help.

[bobss396]

Some TH400 and TH350 trannys are the same length, they swap back and forth easily. I think the magic number is 29.5".

Bob

[cherryelky305]

yeah, some th350's did come with a longer tailshaft. if yours is the longer then it will be easy to swap.

[bobss396]

I played with a lot of combos with Chevys. Powerglides, Muncies, Super T10, Saginaws, TH350 and TH400 all had a common length. The station wagon designated TH400 was the only one I saw that was longer in the tail shaft. Possible that some TH350s were longer too. The hot ticket was to find a rebuildable short tail TH400 and build it up. The cases used to develop cracks in the valve body area, rendering them as junk.

Bob