I bought my 4.15 kit balanced from them and checked it myself. I can check everything but the crank (my brother has a machine shop) which was sent out and checked. Everything came out good. In fact I had to buy 8 more dished pistons from them when I decided to use Indy EZ heads as I had flattop pistons at first to use with 84cc Eddy heads but I had to go to dished pistons when I used the 75cc EZ heads to keep my comp at 10.6. I checked the dished pistons also and the eng has been in my 63 for about 2 years. Ron