the history on this motor is that it was a bluprint crate. 2 pistons ended up with brroken ring lands. Bluprint sold me new pistons /rings and i cleaned it up with a hone and reassembled . this is when i found out about the ring gap fiasco that exists with KB pistons. as near as i could tell they were 26 thou ring gap. when i reassembled i gapped at 32. there was a small mark at the bottom of the 2 cyl that were affected visible after honing. both were at bottom dead centre. so when i was getting a small puff of smoke and a little blow by after the rebuild i just accepted that as normal. when the rings broke in the blow by became minimal, but it always had a small puff of smoke on acceleration until the last pass at the dragstrip when it became a large puff of smoke, and subsequent testing showed one cyl down 40 psi. i will tear it down to check but curious about what i should look for prior. ie; how do i diagnose/differentiate a manifold leak from a head gasket leak. when i pressurize the cyl i likely will get air leaking in the crankcase and the tail pipe is my guess?