looking at upgrading the cam and intake on my 509 going to use either a 500hp carb or efi cam, with that in mind and using the stock rect port heads...which intakes work best ? I know factory used a dart, some like the edelbrock, how about the team G ? thanks Rob

performer rpm air gap

Wilson Manifold recommends the 2902 Edelbrock intake for your type of motor combo. However, using the Dart or Brodix HVH will work very nicely too. Unless your really cammed very conservative, stick (no pun intended) with a single plane intake. Spacers greatly are dependent upon your motor combo.

World Merlin Intake brass lined !!!!!!

Heavy boat... Edelbrock Performer RPM air-gap

Light boat... Edelbrock Victor Jr.

Chris

Rob,
On my 540, I did something a bit unusual. I have gotten mixed reviews from people for doing this. I have AFR315CNC heads, I used a Dart single plain, OVAL port manifold. I gasket matched the last 2" or so of the runners to my rectangular port heads. The thought was that this oval port manifold is a bit smaller than the same manifold in rectangular port, thus keeping the intake charge velocity a bit higher. Here are before and after pics.

DART or TEAM G !!!!!!

thanks, Vinny I have known a couple of racers who experimented with the oval ported to rect heads....they make a lot of torque, was just trying to figure out which intakes were really to big and kill the mid range...currantly have the factory merc performer style with bronze passages...I run in fresh water so not concerned about that...thanks again Rob

I think your best manifold choice at less than 5300 RPM would be with the Mercury manifold you have. If they was an easy bolt -on 10 hp at 500-550 HP Mercury would likely already be using that manifold design. No matter what you do, you could maybe get 10 HP from an intake change and this wouldn't likely show on the GPS. The dual plane style should also deliver more mid-range torque.