AA is too big of an impeller for your motor combo. However, instead of replacing it, you can get the AA that you have machined down. I'd get it cut down to an AB or a B cut for your combo.I heard all this talk about What impeller so i thought i would ask.
I have a 16ft semi v (with gas tank in the bow) with a 468. the motor is stock crank, stock rods 4 bolt main. the heads are stock with a 500 lift cam with a lobe center of 108. Dual plane intake with a 750 dual feed vac sec. over the tran water cooled headers. The pump i just got back from CP PERFORMANCE. they put in a AA impeller. after all that took the book out and only turned 4000-4100 at 58mph on gps. so should I change my impeller or what.