>>>*If the knocking sound continues, then a cylinder leakdown test is in order. At 6500 RPM under load I would not worry too much with the 22RE, they will typically take that for brief periods. Running free is a different thing entirely.

Free running over rev situations normally affect the valve train, at 6500 RPM you would either be in or very near to a valve float situation. This can result in a valve bumping a piston, which might mean slightly bent.

Rough running after could just be excess fuel in the system that takes a few seconds to clear out, but it could also be the system hunting around to find it's own best operating point.

Note excess fuel will cause the computer to "hunt" for a period, this can cause a piston to tap until she settles down.

*I remember a smallblock we were testing once. Dual carbs, 13 to one, around 640 ponies. We threw her to full pull and the return springs popped loose and went flying.

Open headers inside a steel shop, tattletale tach went pegged and would not go any higher. Let's just say we all needed new undies before we got the coil wire yanked....*LOL**....*EB