[Pampered-Z]

OK, my guess is you have way too much lash.

I'd put the pushrods and run them across a peice of glass/missor (something real flat) and make 100% sure they are all straight. Then reset the lash. I would go 1/3, that seems to be were most people are happy with them from what I've read. I honestly don't have any personal experience with them. I've always used the comp Typr R's where an 1/8 is all you need. Take the rocker to 0 lash, go 1/4, turn down the lock, then turn the nut+lock together another 1/8 so your locked in at a 1/3. See if that helps, the promags are slightly noisey.

I won't doubt very highly that your valves are hitting the pistons unless you have a true monster cam or the block decked. If I recall your running a stock block, so your piston is siting at least -15 in the holes. Even with milled heads and .029 gackets you could go in the 630 lift range before you would need to start worrying about PTV.

As far as an exhaust leak: With the engine running take a strip of paper and move it around the exhaust, see if any exhaust pressure blows it. It's pretty common to blow out the ends of the exhaust gaskets, the felpro are a bit thin on the ends ( why coppercoat will help ). Leaks in the center two are often from a warped flange.