I'm thinking of doing an LS3 swap into a '67 GTO. Right now I have the stock 400 backed up by a 4L60E. It's the one piece case design. I'm told that only allows for 5 bolts to the LS3 block, not 6 as with the newer removable bell housing style.

Will this present a problem?

Thanks,
-Colin

 

A lot of people do it. You'll also need a crank spacer.