bck

I'll bet anyone on here lunch and a drink should we meet up that the biggest power improvement this combo will see by far will come from carb/ intake changes. But he doesn't have the room on the boat so...

Gimme Fuel

With carbs or EFI, plenum size and shape can have a large effect. Adding a carb spacer does not only smooth the airflow, it provides a larger volume plenum as well. That is why adding different thicknesses or combining tapered with open spacers can have a large effect.

Let alone if you have an exhaust with harmonics that are not agreeing with your engine, add in intake harmonics that are not ideal, and the losses could be greater than the sum of either issue if they were independently isolated.

bck

Yes. One of the reasons I've asked twice so far what the height of the intake is and whether he's using a spacer. I'm assuming no spacer.

MILD THUNDER

Ive seen where a cam change netted 40hp on a 555ci build bob specd a cam for. Engine picked up 40hp, with a cam that was laying around the shop. Matter of fact, it wasnt nearly ideal for that combo, it was a nitrous cam from howards.

700hp from a 540, with race car headers, 10:1 compression, really isnt setting the world on fire. That 555ci deal , made 760hp. Nothing fancy, afr 335 heads, victor jr. shelf howards cam, pump gas, still made gobs of torque, and the engines went in a 33 fountain with speedmasters.

Offshoreexcursions 572s made 762hp at 6000rpm with cmi headers . Not even big tubes. Afr 335 heads, 680 lift hyd roller, pro systems dominator, 9.8:1,

I can say this, the cams in both those engines , are a world away from what tim has. The heads slightly better, the intake manifolds close in design, slightly more carb than tims 1050s.

bck

Not saying he wouldn't see a change from swapping cams. But I'm still betting the most noticeable improvement would come from the induction setup. Now if he's convinced the cam profile is such that it is physically harmful to the engine then it's irrelevant and he should pull it regardless.

HaxbySpeed

This is something that I've seen over and over on here. How many things do you need to change / upgrade after the fact, to make the power you were promised with your custom cam? There have been a lot of dyno sessions where people have changed out everything from their spec'd/supplied springs, lifters, had their intakes sent off for porting, bigger carbs, cylinder head work, etc. When you order a custom cam specific for your combination, why do you need to do all this trial and error and R&D? Another builder on here tried two custom cams, different springs, different ignition, etc. Ultimately the lack of power was blamed on a restrictive intake. The same one it had when the first custom cam was ordered. An off the shelf grind with a bit more duration and less lift was used, and it made the promised power. It is much easier to carry rpm and power with additional duration, rather then trying to do it with lift and relying on the heads flow capability. Especially when you take the marine exhaust systems in to consideration.

MILD THUNDER

^^^^ couldnt agree more.

Full Force

I have the full cover on boat while over the weekend I was painting my house (only been waiting 2 years) so I can't measure, but correct no spacer.

bck

I ask myself that all the time, but the question still goes further than that. This engine architecture has been around for a long time. Computer development is pretty advanced. Why does anyone ever ask 4100 or 4500? Spacer or no, if so which kind and how big? Anti reversion plates? A dozen different intake choices another dozen head choices. There HAS to be one combination of parts that works best. If I say I want a 700 hp 540 there only needs to be 1 combination of parts yet apparently from all these types of threads no one is sure what that exact combo is.

Full Force

I been waiting since February for proof MY CAM will cause the issues, I seen pics, and see gains over custom cams... But not sure them builds compared to mine, is the shirt duration high lift an issue at 5500? Or at 6000? Or both..?? The issue engine examples I seen are 6000+ so maybe I am ok at 5500... Kip from cam motion says I'm ok, others say not, no matter what I will pulling intakes to see if I see wear or issues starting at 65 hours...