[shark2000]

It would start to over heat when I got on it. But did fine if I didn't hot rod it. Originally, it was a lower I take manifold leak. It leaked coolant into the oil. I replaced it and check clearances on everything. Everything checked out good. So I put it all together. Come to find out, it had a crack in one head, between the valves. I changed out that head and when I started it, it had a knocking sound. Figured the I just needed the hydraulic lifters to pump up. It got a little quieter, but still sounded like one thing still making noise. Finally after the engine heated up to normal operating temperature, it final got quiet. I shut it off. Next time I start it, it's noisy again. It takes a while to get quiet again. Eventually it does. I wasn't sure if somehow the rod bearings went bad, so I changed them, plastigage shows clearance is fine. That's when I notice this clunking noise, just by turn the engine by hand, when the #1 piston is at top dead center.