Hello Tom...I do not currently have a tachometer...I would like to get one. Gil is currently getting excellent results with little more than bore polish and shave top of piston...its a very easy task IF you have access to a lathe? They sound SO much closer to the full size size versions I feel it's worth the low effort. However...if you can not easily gain access to a lathe, I Would wait till U can...your mileage may vary.