Is the transmission bolt pattern on an inline 250 engine the same as on a 350 V-8 engine? I'm wondering if it is as simple as dropping a 350 into a '77 Nova to replace a 250 6 cylinder and using the existing transmission, driveshaft, etc. Anyone know?

The bolt pattern should be the same. It was on my 67 Nova. I've had Powerglides and Turbo 350's in it.

All Chevy 6 Cyl And Small Blocks Have Te Same Bell Housing Bolt Pattern

That's correct, also you will need to change the frame mounts for the sm blk to bolt to the sm blk motor mounts. Also v-8 throttle linkage and reroute the full line. You might want to find a longer spacer the move the fan closer to the rad. :2cents: