Racer Brown ST-21

10.5 would be minimum for that cam if it really has [email protected]. That's a bungload of duration and will bleed off an equal bungload amount of cylinder pressure. But you should verify those specs. It looks like you're getting different specs from two different sources.

...and dynamic compression is also referred to as "running" compression. That simply means the compression ratio with the camshaft in consideration. Static compression is the compression ratio disregarding the camshaft. If you go to United Engine's web site, they have some nice calculators that'll keep you busy a while figurin all that out.