Maybe 16,500 needs to become 17,100 or something. I know I have 3 TT Pro .40s, they are all box-stock, and each of them turns an APC 9 x 6 at 17,000 even. That's with the muffler as supplied (JB Welded together), no changes to the head gasket, bearings, or anything.
The rpm limit can't be your only engine rule; all it can do is provide a quick-and-dirty indication that perhaps the engine isn't stock. In fact, some cheater engines actually turn
less rpm on the ground because they've got higher timing. There's no substitute for inspections.
Just my .02 ... where should I send my SEMPRA dues?
Duane Gall
RCPRO