I had a set rebuilt last season for a friend. He had gils with silent choice and had problems. THe cause of the problem is the water enters the gil tails in the elbow. I had a guy build me a set or tails that introduced the water 1 1/2" from the end of the pipe and that fixed it. Also with a big cam and the silent choice I couldn't get it to work without sucking water.

The gil's have three different top elbow pieces. Different hights! My buddy's are stock and are definetly not the low ones, I wonder if yours were?

Andy Bloom,
Next time your at the shop we need to talk horse power instead of airfoils. Also I am way ahead of you, when I was removing the silent thunder this winter I saw the end of the pipes were the old style, so I took them to my top secret friend in painsville and reworked them to the new style. I installed HPI silencers for a much better sound than the silent thunder .

I notice that we have some other people looking for the same thing that I am out of the HP 500. I work with a local race engine shop here in northeast Ohio, I send him some work and use my boat for real results and he helps me. We would like to place an order with AFR, I will be purchasing 2 sets of heads, If we can add 2 or more sets to the order we can get down to wd price plus a little for the shop. P.M. me if interested. Jeff

only 600hp with AFRS? I thought the hp numbers in the magazine showed 200 hp gain ?Sounded too good to be true or is it?

Plumbers Crack,
That engine was cammed much larger than what we need in our pleasure boats. The boat would fall on its face from loss of low end torque and never hit the rpm needed to make 700+ hp. I chose the 741 cam as a starting point for this combo, but I must agree with some of the previous posts in this thread that a custom ground cam that might have less duration than the 741 might be the way to go. I thought 600 hp was a realistic and obtainable goal, I will be the last one to complain if it makes more hp. Jeff

WAGS382
the crane cam 741 looks like a good starting point. it very similar to a custom comp I have ground. sorry it took so long to get back to you very busy at the shop .

CMS Racing,
Thanks for the reply. Do you think the 315 is too big for the 502?
Jeff

I like to run aruond 300 to 305 int runner on a 500ci motor that is only going to make power to 5500. to 5700.

On the AF heads are the exhaust ports raised? With the motors side by side this will push the exhaust 1 inch total closer to each other.

On my 2001 500efi's with the cmi headers I don't think there will be enough clearance. What da ya think?????