thanks Glenn, but now that i think of it, stem seals shouldn't have anything to do with compression as the valves are seated against the head to close off the cylinder during compression.
the valves stem seals are to keep exhaust and intake gases out of the valve cover during intake and exhaust strokes... ...right?
96 F250 SCLB 4x4 7.3L PSD - RED
(RIP - the part out has begun)
97 F350 CCLB 4x4 7.3L PSD - WHITE (361k mi - DD, auto->ZF5, 3.55LS, 6637, 3"DP->StraightPipe, 33x12.5x16.5's, object of more upgrades)
97 F250 RCLB 2WD 5.8L gas - BLUE
(ZF5, 3.55, distant-future-project-truck - 235k mi)