Overheating issue with March Performance pulleys

I went through this recently and feel your pain, though it was with factory pulleys not March. Typically when you buy the AC pump (for other OEMs anyway), you're getting a higher flowing deal, but not on a Mopar. Chrysler used a smaller pulley on the AC cars, and compensated with less vanes on the pump. This is apparently secret knowledge because its not published anywhere.

But my question is: Why not just get the better pump and keep the pulley? You can get the pump at Autozone.

I don't see how its March's problem if you've got the wrong pump. Everywhere I've ever seen those pulleys, they've been advertised as underdrives. On March's page they go into the exact measurements and give options for differing water pump pulleys.

http://www.marchperf.com/pg43.html

Again, do not take out the thermostat.

Seems like there's something wrong with the valvetrain also. Probably pushrod length, but it could be a lot of things. How much P/V clearance are you running intake/exhaust? Did you check it?

Unless you made some part changes on the latest rebuild, I'd expect to have messed up pushrods and valves again soon. Its not going to just decide to quit eating parts.

If you get tired of running race gas to kill the spark knock, you can probably install a camshaft with a later intake valve closing event to bleed some dynamic compression and go back to pump gas.

Steve