I have stock 502's with gil exhaust. Recently came across Merc 525EFI intakes with ECM. What Cam and Head combination will get me to 600HP without using blowers? Thanks for you help.

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I can put you in touch with someone who can make that kind of HP without blowers. He is in S.Florida.

Call me 516216 0778 I can help you with the combo

Stroke em

You're going to have to do a bunch of work to the intakes to make over 600 hp. You will also want to install a larger throttle body. I have done a few with intakes from 500 efi's that have been extrude honed and had the largest throttle body I could get and just barely broke 600 hp. And that was 555 ci. I wouldn't try it again, just because it wasn't a very good engine. I changed the intakes on the dyno and installed a Holley injection setup that I typically use, and it made 85 more hp on the first pull. I did the swap on the dyno in a few hours. I use the Holley setup with a Mefi 4 computer with there 2000 cfm throttle body. Give me a shout if you want more info or if you have any questions, Eddie.

Isn't the 525EFI intake better than the 500EFI ? Doug

We did 620 @ 5700 with 502, 9.3:1, hyd roller cam, KE pipes, 850 on top of a HVH Brodix and Canfield heads. All parts "out of the box". KE used to have a 502/620 package.

Those KE Headers are the BEST! I have a pair of HP500 Carbs sitting in the Mystic shop, that I'm going to try to get the most HP out of them, w/o blowers and run 87 octane. KE Headers will be on the list, the Canfields or AFR's are one of the decisions that I have to make. Are your Canfields hard coated for saltwater use?
Dean

I thought that just the throttle body was a little bigger, but the runners were the same. That is the impression I got, but I may be wrong. There are a few external differences, like the MAP sensor, IAC, etc, but I thought they were the same internally. They do good up to about 575 hp, but anything over that and it just wasn't a good engine. It went very rich on the top end and the power just fell off over about 5000 rpm. You should have no problem breaking 600 hp with a different intake and throttle body or carb.

Here are afew pics of the efi setup that I use. Been using it for years and could not be happier.
Eddie