50 HP duh lol

As many times as guys like to mention what happens when you go too big on duration, theres 1000 times more scenerios, where not enough duration, was causing a lack of power. If not , we would all be running stock cams in everything.

How many guys many years ago, took out a stocker cam from a chevelle, gto, buick, stock 365hp merc motor, or any of those, and made more power , by going to a camshaft with "less" duration.

Of course if you get carried away, then things go bad.

CAM and ECM computer Program. I had a buddy upgrade his. That is all it took. Pretty much added 55HP.

found this on an old thread

The standard marine 8100 cam is:

204º/209º @ .050”
.282”/.284” Lobe
.480”/.483” Valve
118º

The HO cam:

224º/233º @ .050” (222º/232º)
.300”/.300” Lobe
.510”/.510” Valve
114º/115.5º

The cams are ground on the C swap core.


496 MAG (375hp)
Block: Cast Iron
Cylinder Head: Cast Iron (with exhaust valve seat inserts)
Intake Manifold: One Piece coated Cast Aluminum
Crankshaft: High-Density Nodular Iron (with undercut and rolled fillets)
Pistons: Hypereutectic Cast Aluminum
Connecting Rods: Forged 1141 SAE Steel (short -peened and magnafluxed, with 9-mm diameter connecting rod bolts.

496 MAG HO (425hp)
Block: Cast Iron
Cylinder Head: Cast Iron (with exhaust valve seat inserts)
Intake Manifold: One Piece coated Cast Aluminum
Crankshaft: Forged Steel (with undercut and rolled fillets)
Pistons: Hypereutectic Cast Aluminum
Connecting Rods: Forged 1141 SAE Steel (short -peened and magnafluxed, with 9-mm diameter connecting rod bolts.

Both are internally balanced. Besides the above, there is a different cam and programming between the two.

That's why loading as low on dyno as possible can help us to put all the #'s together .when looking at various charts.

Most black motors, if not all, can pick up a bunch of power at planing rpm and all the way up and beyond with a modern performance cam change.

However, when you are near maximized, changing duration will just change rpm range.Add some up top, you'll lose on bottom..and vice versa.

Hopefully I wrote that so must understand. Hard to type my brain sometimes. LOL.

Tim I've kinda got away for a bit but back to original thread I'm curious what most are doing for 540 build combos in your boat. Your builds obviously need to be tailored around your specific application is for certain. Just moving forward if you reached your goals with said cam you posted and optimize head and intake velocity with pushing peak torque to near 5k what end result would be. I know Joe among others touched on how much rpm above peak torque you would end up propping to. I guess in a nutshell regardless of hp, "what are others running peak torque at with your specific boat"? It's obvious what you have isn't working so I'm just thinking out load but will probably get bashed for that. What should peak torque be at for your application? Obviously makes a big difference from let's say a cat or even fountain.

Both new and old cams have the 4/7 swap. It was replaced with a 252/261 113LSA .663/.671 if my memory serves me correctly. I wanted to go to a .400 lobe though and I'm going to give it a try here very shortly.

The reason it performed better then what was in there is the higher lift profile combined with the full CNC Brodix heads. The comp cam wasn't bad, it just wasn't ideal so I had it tweaked a little bit.

Most of the time when we add duration we don't do anything about loss of cylinder pressure. Loss of power result.

Tim, so what were the cam specs used in your old 565 cu in engines with the Pro-Comp heads that were supposedly stronger?

I'm seeing more and more of the 4/7 swap. That's one thing I haven't tried yet however at least read about the majority claim gains throughout. Are these near future builds going into your Apache. I'm also seeing most custom cam splits seem to be in the 5-8 deg range. I realize this can be build specific however do most agree this fits best with majority with us that are using similar combos/builds. What determined your split? I was looking at some 10 deg splits with slightly more lift on 565 NA builds but not a 100% certain yet.

Interesting thread regardless. Lots of info.