[leegreen]

I hope the engine can be fixed. If the bill looks to be more than it is worth, just bolt it together and run it as-is the worst that can happen is you wreck the block - which is probably the cheapest component on your engine right now! That plastiguage result looks promising and your oil leak should be fixed.
For a different perspective and meaning no disrespect to your engine builder's experience but in my much more limited experience I don't think warped heads or coolant vapor locks are common occurrences on these engines. I can't speak to the need for an extra key in the crank nose for a supercharger, but the stock engines never had much issue with spitting the pulley off and unless you drive it hard you are not putting much additional strain over stock.

With a new corvette to fill your speed needs you don't need to build this truck in that direction unless it suits you!

You can also get a 'crate' rebuild of a 250 or 292 inline 6, you don't have to go v8. you'd need a bellhousing, maybe adapter ring for the car 4 speed, side motor mounts. Everything else you have should work with a little tweaking.

you'd get 150 - 175 HP, which is probably more than the blown 261 can produce reliably. This is in keeping with the rest of the systems on the truck you built to match the 235, so you don't have to start thinking about new suspension etc.