Have you had the cam out of the block since you put it together and ran it? I would bet my next paycheck the cam is twisted and once you take it out it will not want to go back in. I had similar issues with a big block 7500+ rpm and a 55MM cam core fixed ALOT of issues and made more power. To get that kind of lift a stock cam core is really small. Look at the base circle and think about what that thing is doing with that spring pressure and 7000 rpm. Big cam core and pushrod oiling through the lifter will fix a lot of things.