if you fit the cams in to the head, then try and bolt the chain wheel on the cam slides back about 1/8 of an inch,, this is enough for the flat of the washer to miss the flat on the cam.
this means the cam is NOT located and is NOT timed correctly.
.....

remove your washers and look at the back face, it will show damage if you got it wrong.

but if they are regrinds did you get verniors and time them up correctly? also have they been ground and the lifters dont reach now? do you know how much less the base circle is? do you need to fit shims under the lifters?

tony