If that's the basic $1500 Goodwrench crate engine, I see in a GM catalog where they list it as 8.5 in one section and 8.0 in another. But it's actually closer to 7.8:1.
Anyway, the last thing you need to do is close the intake valve too much later on the compression stroke, otherwise you will bleed off more cylinder pressure, which kills power. Here are two cams that should work:
Crane P/N 114112, Grind Number 2020
I used this cam in that very engine in a 69 C10 with a 3.08 axle. It actually closes the intake valve sooner than the stock cam. And it makes a lot more low-mid RPM torque. So much that I could drive up tight mountain roads one gear higher. Only downside is it quit pulling at 4500 RPM, if that really is a downside.
Summit P/N SUM-1787 (same as Crane 260-H10, I think)
With its wider LSA, this one would spread the torque over a wider RPM range than the 2020 cam, and certainly let the engine rev a little higher. And its intake valve closes only a few degrees later than the stock cam.
Other cams in the 204-208 intake duration might work, as long as you keep the LSA at 100 or below. Isky makes a cam that is 208/208/108, which I've always wanted to try in an 8.0:1 engine. And there's someone out there who makes the very popular 204/214 cam on a 108 or 110 LSA, Sig Erson, as I recall.
Have to add that I know two guys running the stock cam in that engine. One in a 51 pickup, the other in a 55 sedan. Both of them really like their engines. And with a small 4 bbl, headers, and 34-36 degrees total advance (+ vacuum advance) they are anything but dogs.
