i got a race prep .24 eb mod and it had no shims. I had good bottom and no top, like i was missing the upper 20% of the rpm range. after i blew my third or forth plug i disassembled it and found no shims. So for those of you having some problems I would check the shimming. I already had some slop in my rod after only eds break in and four tanks by me. I sent it in to chad to take a look at it and he said i would have a new engine by the end of the last week. still waiting but i am sure he is a busy man.