the duke

Dave,

you posted your stuff before I could use you as an example.

The 741 works great with the AFR heads. There is no reason to pay extra for a "special" cam, unless you are looking for an extra 5 or 10 HP which means nothing in a marine motor.

As far as just plain heads go, there are AFR's, and then everything else. (unless you want to go with Pontiac heads). AFR's aren't cheap, but if you want to have your engine set up to make the most possible HP they are the choice.

MrCIG

iTrader: (1)

DO you have solid pipes straight out the back or a rubber hose connection? With the solid pipes I don't have much movement.

I did read this on the AFR web site

"Also, be aware that our exhaust port location has been raised .300 over stock height to improve flow characteristics.
If you are currently running stock heads and you have a very tight header/exhaust manifold clearance, you might be forced to modify them to fit."

It is raised half the distance of the Brodix and Canfield. But i'm not sure if it will make it still

Mark

axapowell

I'll look for a picture, but I do have about 1" between the end of my tail pipes and my thru bolted transom mufflers which are connected together with rubber. If they were going straight thru, I think they'd be fine. Let me look for the picture.

Dave

MrCIG

iTrader: (1)

Thanks for the offer Dave. We torn the one motor down today. Found a valve guide disappeared into little pieces and imbedded itself into a few pistons.

Bottom end looked like the day we put them together 350 hours ago.

Looks like it's time to get rid of the old GM Steel Heads.

Mark

axapowell

This is the best I have of what I think you are looking for...

Not a bad thing to upgrade!!

I'll look on my other computer for a better close-up later this week!

Dave

KAAMA

iTrader: (1)

Mark/Mr. Cig, my boat eventually went from cast iron Merlin heads, to Dart aluminum Pro-1's to the 315cc AFR's which I now have and are supposed to have a thicker deck. The center to center dimensions were important to me because I have a hatch actuator that is mounted on the center stringer between the engines/headers and I still didn't need to change the cut-outs where my tailpipes go thru the hull with the AFR's. So, if there were any changes I couldn't really see them or notice them on my boat just by eye balling it.

axapowell

Same observation for me as well!!

Dave

PatriYacht

Hi Mark, glad to see you're stepping up to the AFR's. With a 522 and a cam that large, your power peak will be about 5800 rpm. A 598 will be a torque monster with the same components. I would think about AFR 335's if you're going to build 598's soon. Custom cams are no big deal. Comp Cams maks them for about 40.00 more than off the shelf. Mine is 236/240 @ .050, .630 lift. AFR's benefit from less exhaust duration because their intake to exhaust flow ratio is so much better than a stock Chevy head. If you want the grind number for my cams call or send a P.M. Good luck with the new build, Ian

MrCIG

iTrader: (1)

TTT for a friend

Thanks for all the replys

Mark

Crazyhorse

You're welcomed.