KAAMA

John, I am using the 315cc AFR CNC ported heads on my naturally aspirated 565cid engines, with dart single plane intakes, 950cfm Holleys, 9.5cr, 34*timing, and very mild hydraulic roller cams that will as low as 600rpm or so in neutral.

I have a friend with a pair of 556cid surpercharged engines with Dart Pro-1 heads with some port work, with dyno sheets that show the engines SUPPOSEDLY making 810hp. I seriously doubt that is what they actually make, but that's what the dyno sheets say----and he has the same conventional V, 32' boat/hull (none stepped hull Active Thunder) as I have. I have a little different set-up (extension boxes, IMCO 2" shorties), than he has, but from about 3000rpm on up side by side he cannot pull away from me----I cannot pull him either. I'm sure he was thinking he was going to wail on me with his supercharged engines. We have done this a few times and every time he said he was light on fuel and my tanks were always full. He seems to be a bit surpirsed that he cannot pull me on top or in acceleration with his supercharged Pro-1 headed engines----but he's having the engines freshened as we speak and making some changes while he's at it. So, this summer he might be anxious to show me that things won't be so close as they have been in the past---GULP!!!

Last fall with full tanks I also ran up against a stepped hull 36' Apache in flat water with a pair of 540cid Vortec supercharged engines with ported GM heads that make something like 815+hp---his boat runs really good, but I was right there waving hello to him side by side down the stretch. Just having fun that's all.

Anyway, just wanted to let you know how well the 315cc AFR's ran on my 565's. By the way, I was one of the guys who took my AFR's to JimV's shop for some exhaust port work as he has described. Have fun.

Bob280Silencer

Couldn't get enought air thru a 1300 cfm T/B on a 500efi with 315 AFRs? I always thought the lower plenum was the restriction? Looking forward to seeing this new "top" BOB

cdscarab

What kind of improvement in TQ & HP might one see if a set of AFR 305s were installed on a 454 mag mpi? Given better exhaust & reprogramed ECU.

Thunderstruck

I saw 1.2 hp/cubic inch on the dyno (no accessories or marine exhaust) with 305 cc AFRs and custom cams. Started with carb 500 hps. Motor made 615 ft lb of torque at 4200. Bottom line, the boat picked up 5 to 7 mph, the real yardstick.

Kidnova

cdscarab - I have a set of new AFR 305's in the Swapshop if you're interested. Reason for selling them is in my add.

I'll be out of town 4/12 & 4/13 so if interested I will not be able to respond until 4/14.

Nice to see a local guy on board here !!

Bill

KAAMA

Glenn's had a pair of 565cid naturally aspirated engines built with 315cc AFR CNC ported heads, 9.3cr, tunnel ram intakes, MILD hydraulic roller cams and they ended up making something like 718hp @5400rpm on the dyno with alternators, belts and pullies, etc. I kinda thought 700+ HP is pretty respectable @5400rpm for a NA engine with those cubes and mild cam. I wonder what kind of power Glenn's engines would have made if he had wanted RMbuilder to design a cam that made power up to something like 5700-5800rpm???

Dave Wesseldyk built/dyno'd the engines and RMbuilder/Bob Madara did the cam app.

Kidnova

KAMMA - Hopefully, in a month or so, we'll see what a 557 at 5700-5800 RPMs with a rmbuilder tight lash solid roller will do. Oh yeah .... AFR 315s