[mike50gt]

a few months ago i got my motor rebuilt and i decided to get a cam installed it was the ford racing x303 cam and i used my stock heads but the guy that rebuilt my motor said i should use gt 40 spring because they can handle the lift better or something like that so he put springs on stock head and after i started driving my car ran like crap it died all the time come to find out that cams for a mass air car so we took cam out a put stock back in but back to heads my motor has a tick i changed lirters pushrods and rockers could it be gt 40 spring on stock heads

[noble steed]

Could be the springs, also check the injectors, serpentine belt and accessories, check for exhaust leaks. Could also be piston pin wearing out. Do you have roller rockers?

[RLG34750]

why would a mechanic put an x cam in motor with stock heads...

could be a rocker backed off or possibly an intake gasket ,exhaust leak....

[mike50gt]

yeah it has roller rockers

[noble steed]

Were the RR's adjusted properly? Some require .002 clearance from the valve stem....some require zero lash...

[mike50gt]

not sure i just know when i put them on i snuged them up and same noise and loosen them a little and no change in noise