you can square off the aft corners of that crank where the opening is from the carb.
Also the brass sleeve which engine is that for? if you measure the timing on it you need to average it for the highest and lowest opening for the exhaust port. IE: the peak maybe 185 degrees and the lowest might be 175 for 180 average open for exh.
I have found that on most engines the "turbocut" didnt help the lower rpm engines for most planes. it could be the small gain is offset bt the increase in crankcase volume. I will say the same for the knife edged rod had a small gain 50-75 rpm. that could have been just change in pressure. lol
I do know very good positive with the AAC is less weight and better heat transfer to the case.
When you going to run it?