Anybody have experience with these heads? They claim 175 HP over stock GM Iron heads. They don't say what stock GM head they are comparing against.

The horsepower gain may be determined by cubic inch and usable rpm range.

At 7000 rpm maybe. On a HP500 maybe 75 hp if nothing else is changed other than carb jetting.

I'm running them and like the power they are capable of making. I think they are one of the best middle of the road priced heads,Smitty

The Afr Is A Quality Piece For The Price But Also One Of The Best Working Conventional Heads Out There. As Far As The Power Gains Every Engine Is Different.

We run AFR CNC ported heads on our 97 Merc 600SC ,roller 509CI TopGun motors,now an easy 800hp+ @ 5800rpms, only 6lb of boost..
I think the CNC ported AFR's are a good choice right out of the box!

1997 -10,500 lbs TopGun 94 mph gps. We gained 12mph over stock motors with the addition of AFR heads and of course other well matched components.

check out the thread on SW, "hp 500 back by popular demand"
he used the cnc heads and made some good power....two motors and similar numbers!!

Have heard noth'n but praise on these heads. CanDo

boatn70 was referring to me. Depending on what you are looking for, I just completed dyno running my HP500's with new 315cc CNC'd AFR's. I'd be more then happy to fill you in.

Dave

I have a set of AFR 315 cnc on my NA 540. No problems to report, the best thing is they made good power through out all rpms.