[greg64]

Chuck, I don't know the SM318's diameter, but the bellhousing is 4-11/16 or 5-1/8 (the SM465 one). Plus, the Muncies and T10, etc. use the 4-11/16, so I'd be really surprised if you're going to have a problem here.

As for the T5s, they are weirdos. I'm pretty sure there are input shaft problems if you were to use them behind a SBC, although that is what was done in the 3rd gen Camaros, but again, that's a bit weird because the bellhousing in that application rotates the transmission off the vertical. So, it's possible that this corrects for the input shaft as well.

The S10 T5s I'm familiar with were used behind the 2.8V6 and 4cyl, and the V6 has a bellhousing that is different from the standard Chevy V8 design.

I think the bellhousing that can match the two is the one from the Astro van with the 4.3V6, but how many of those had a 5 speed?

Bottom line, if you're considering the T5, do your research because there's been a lot of variants over the years (especially when you consider the Ford application with the WC-World Class).