RE: Are the new Thunder Tiger 40s actually 46s?
Be aware that the crankcase of the TT has changed over the years and accordingly so has the head gap. The older crankcase design does not have machined cooling fins, the new ones do. The head gap is different between the two designs. We saw this last Saturday while we were looking over the engines in Tuscaloosa. We had a good mix of old and new engines and were comparing the differances.
I'll try and post some pictures of how we will be checking the engine displacement. It is very simple but not everyone will know how to go about this.
If you have a spare engine that has been checked, please bring it just in case someone finds out their engine is not legal.