305 Question about valves
 

Is a 305 an interference motor or not? In other words, if timing chain or gear breaks/stretches will valves hit piston or is there clearance? Some Chevy motors are interference motors and some are not. Don't know if GMC 305 V6 is or not? Thank you.

Re: 305 Question about valves
 

The 305 is a non-interference motor. I have measured the valve clearance on a stock 305 head and a magnum head. On the 305 with a valve lift of approximately .450" (valve wide open) lift it will still have a minimum of .150" clearance (piston at top dead center). On the magnum head with a valve lift of approximately .450" (valve wide open) lift it will still have a minimum of .120" clearance (piston at top dead center). Hope this help.

Re: 305 Question about valves
 

Thank you very much James.