The one I just rebuilt and dropped into my 68 K10 4 speed to replace the 250. I found a new set of LP pistons...They are rated at 9.3 compression ...I cc'd the piston depression, cc'd the head ,block was milled .025 to get a reasonable quench and the measured compression is 8.95-1. Bought a mild Schneider cam and just used the intake and exhaust manifolds from the 250..
Started right up, went through the 2000 rpm cam break in and then out onto the road...
It's a lot more snotty that the old 250. Has a strong sounding smooth idle with no lope, pulls nicely through the gears...With the limited intake and exhaust it's no high rpm thing but more than adequate for my purposes...
No one can say the engine compartment is over detailed
