I am having a little difficulty trying to determine what the problem is. On the first 500 miles of break-in, I had power that would spin the hell out of my tires and that would only be at 3/4 throttle. I understand that fact that I changed to MT ET Street tires, but I should be able to spin those up atleast around full throttle. The engine over heated once and I did test my compression and one cylinder was at 180 psi and the other cylinders are at 190 psi, Changed the hydraulic flat tappet cam, springs and lifters, verified valve lash is at 0, timing set at 36 btdc. changed to an aluminum water pump,installed new intake and exhaust gasket, changed plugs, changed to an Pertronix HEI race dizzy, new plug wires, new stall converter, new Holley electric black fuel pump w/ reg. set at 6 psi, had carb cleaned and power valves replaced since one was blown and thermostat. It also has no more power after 6200 rpm, just stays flat and will not pull anymore, but the engine doesn't break-up or no type of engine miss.

You guys have any clue that could help me out? I am thinking maybe something wrong with the heads. Checked cam lift and springs again and no problems there.

 

First guesses are: Ignition isn't doing what you think it's doing; valve float.

 

But once valves float, can't you just fix that with replacinig valve springs which I did when I changed the cam and lifters.

 

yes you could have fixed it by swapping out the springs as long as the new springs have more preassure and the new cam isnt already to big for them