What should the compression on a 2.8 12 1/2 to 1 engine be?

e.j.

what kind of cam?

high-overlap (race) cams often show "relatively" low static compression.
most important are cylinder-to-cylinder numbers.

if you're trying to establish if there's a compression loss, this is one reason why leakdown tests are preferred to compression tests, which don't tell you much, except in comparison to the last compression test, assuming it was made at the same temperature, barometric pressure, and altitude (too many variables...)

i'd *guess* with an RSR sprint cam you might see numbers in the 150-165 psi range.

anything lower than maybe 120 or higher than 200 *could* indicate a problem.

About 185lbs, but as mentioned above, the cam profile/timing have an affect on compression