I've spent the last month swapping my stock motor for a new GT-40 crate motor from ford racing. It has the E-303 cam and X-302 heads ("340 horsepower"). I put a typhoon intake on it, 70 mm tb/egr, 24# injectors, calibrated mass air, all new accessories, new clutch, pressure plate and throwout bearing... I got it running, and adjusted the timing. the timing has been between 10-20 degrees just to try to get it to run right. I left the valve covers that came with it on it. There is a banging coming form the intake/can hear from filter. I assume the valves are not opening and closing at the right times. Could this be because of the rockers hitting the valve covers? I think it says "for shipping purposes" on the sheet that came with the motor, but they had gaskets. One of the valve covers looks like it has a scratch/indentation in it. A previous post said that on the same motor the valve keepers needed to be adjusted or was "held back by ford"... what does this mean and what can i do if i have the same problem?????????? help!!!!!!