Shake

When i start my car it shakes like a damn earthquake. It shakes when the rpms hit around 1000 to 1500 but after that its fine. ive heard its motor mounts or harmonic balancer, i just put in a king cobra clutch and had the flywheel resurfaced. Has anyone had this problem or has any idea what it is. it puzzles alot of people and everyone has a different answer.

thanks for the compliment, yeah ive been reading and hearing about people having this same problem and getting a new harmonic balancer. looks like thats the problem. Im taking it to this guy this week that i know and his gonna check it out