elliss12

iTrader: (1)

This is kind of an odd one so its going to be long and detailed, I apologize beforehand. 90k mile ls1 shortblock, good visual condition and clean, put 799 heads on and ls6 cam and 7.4 pushrods. I screwed up and had cam timing off, fixed timing and engine ran good. Later on developed a misfire once you drove the car and reved it up, found that cylinder 7 had 150psi compression cold while others were 210, compression would drop to 100psi once it started to misfire. I found bent pushrods so i pulled the heads, replaced all valves, put in a 228r cam, and got new pushrods. Engine started and ran normal, drove it and beat on it, same misfire. Now cylinder one has 150psi compression, 100psi once it misfires. Cylinder 7 has normal compression now and no misfire. Leakdown was the same on all cylinders and only audible leak was past rings. I bought an adjustable length pushrod checker, looked like i had a little too much preload so I went with the 7.35 pushrod which put me at .080" i believe preload. No fix there either. I pulled the engine and heads, found no cracks on the head, piston has no cracked ringland or abnormal wear, rings move free, cylinder has no scoring. I'm basically stumped at this point. If I had to guess, its rings or lifters pumping up or something stupid. Any help would be much appreciated. Thanks