A-904+rear end, HP ratings

I learned the hard way, raced my 66 cuda with 318 and 71/4 rear. Was ok until I made motor go faster and ran more rounds (got better). I made it to final round one day and sure enough, on the line right after semi round it went clunk. I took advice of many and found a good 83/4 rear had it narrowed and built for my needs. This cost me about 3k total, but I could not hurt it with 318, even as I improved Hp going into the 400Hp range. Car ran low 13's and was consistant and never had mechanical issues! I was good racer at that point and made many rounds and finals with no more issues except opponent! Spend some money now and you will be happy and never left on side of road or track. My current 65 is going to go through same process once paint and body are done. 318 built and when ready I will find 83/4 rear to go in along with my already built up 904 trans. Good Luck and enjoy the ride!