Cm871 vibrating and tapping like noise at 1250 and up.

[Husky05]

Got motor mount replaced, it was in a really bad condition. Now I don't feel tapping or anything. But still the engine is shaking 1250 rpm and up. Feels like something is off. Maybe fuel delivery isn't enough. But I wonder what would happen if the previous owner put in a different cam or crank keyway key? What would that cause if I ran stock timing with the wrong key?

Engine shudders under 1350 rpm still like I'm trying to go up hill at 1000 rpm.