Hey Tracy,
The Rattler fits ABSOLUTELY PERFECT! Lines up Perfect etc! It is about a 1/4 inch thinner than the PRW balancer also. No shimming etc. It is expensive though. Maybe call Brian at IMM, He used a different one on the 410 he just built and I know it was inexpensive but I dont know what brand it is or if it is SFI Approved. He did run an alternator in the car but I dont know about a fan.
I didn't have to heat it up or anything and it slid right on perfect........I like the Rattler alot but out of the question for this one!