Twisted6 knows his stuff. I agree with him completely. I think another problem will be what you can fit in the engine bay. If a 292 will work, then have at it. If not, then the next choice would be a 250. Good luck. John

BTW, I'm pretty much wanting to do the same thing as you. Hopefully I can find a 292 and boost the snot out of it. \:D Fun times.

'68 C-10 - 250 with Edelbrock 600cfm 4 barrel, Offy intake, Hedman headers and true duals, HEI, MSD 6A box, relocated gas tank
Soon to have: T-5 tranny