I also have a 474 ltr. Mine is the 13.1:1 wiseco. +2 intake and exhaust, hotcam intake, full port and deck. I have the pim 2. The original map i got from williams perf out in florida was not very good. In fact i was getting beat by my old ltr that was stock with a cherry bomb. I ended up getting it dyno tuned. The guy hated me by the end because he promised he could make it right. So 36 dyno runs later and a lot of adjustments it is pretty solid. My dyno chart says 45hp, but outruns "60hp" bikes. Dont know, dont really care what numbers it makes as long as it works. Still doesnt have a perfect low rpm off idle i think thats kinda how they are with cams. My best recommendation is find someone with a dyno and experience with the pim2, spend the 2-300 dollars and be done with tuning.