Bumpstick ???'s

[AZKC]

Looking to upgrade the cam in my 454 jet. Leaning towards the Comp Cams extreme Marine grind. Specs are 244/254 duration and .570/.575 lift. Anyone tried this one. Running 750cfm for now on a Performer intake. Boat turns about 5800 @ WOT thru a Panther Jet with the setup thats in it now.
I think I saw the power band on that cam was from around 1500 to 5800. Seems like a OK choice.
What do you all think?
KC

[LeE ss13]

I think your looking at the 11-244-4 hydrolic cam, but I think the power range is listed at 2500 to 6500. Get the good springs with it, part number 924-16. I have heard that this is a good jet boat stick. The 112 degrees of lobe separation makes the cam very forgiving.
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LeE ss13

[MikeF]

AZ, I don't have any experience w/ panthers but before doing any work to the engine the pump should be made as efficient as possible. Then you can use all the power from the engine to move the boat forward. :D

[miller19j]

I was thinking about the same cam and was hoping that one of the engine gurus would chime in on this one. Come on guys anyone?

[Omega21]

Miller & AZKC
Not really an engine guru, but list the details of your engine, and I can plug them into Desktop Dyno for you. Some say it's a really accurate program...some say it's ballpark numbers.
Need to know:
Cyl head type, Valve sizes, port work?
Comp ratio
You already said 750 & a performer intake, I'm assuming gasoline for fuel (no nos)
What Exhaust (wet headers I'm assuming...logs?)
And these specs for the cam...which are gonna be a complete trick to get for a CompCams camshaft..which is exactly why I'm not going to use one in my Olds motor:
IVO (intake valve open in degrees)
IVC (Intake close)
EVO (exhaust..you get the picture)
EVC
Lift for int & exh.
Todd

[AZKC]

Todd, heads are stock oval port with 1.725" exh
2.065" 9.5 to 1 comp camshaft has .570 intake lift
.575 exhaust 244* Intake duration 254* exhaust duration. Running "logs"
That enough info....
KC

[396_Z]

I'll go ahead and field this question...
I'm not sure of the advertised duration and a couple of other specs so I'm doing a little guessing on this but the RPM range on that cam should be from about 2500-6500, it's going to want around 10:1 compression because of the cylinder bleed off, don't go less than 9.5:1 that wouldn't be enough cylinder pressure. Your going to need to do some head work because of the lift, cut the valve guides down and enlarge the spring pockets. That will take care of the lift and spring diameter problems. A good port and polish job would do wonders for that cam, were talking 40+ hp there. If you do have the head work done leave the intake side rough from grinding and polish the exhaust side glass smooth... I can explain that one if you want me to. Your going to need long slot or roller tip rockers, the roller tips will help the valve guides and seals last longer.
I personally think you'd be pretty happy overall with the engine, the XE series are some of the best cams available today.

[77charger]

what is the condition of your pump?If it is loose when you freshen up that cam will choke.I would use that cam if you have min 10-1 comp ported heads,+intake headers,850 carb.That cam will want to make peak hp around 6500 rpm.A good choice for a smaller boat say17-18 and a b or c cut impeller.As for panthers i dont know shit about them.
I have learned fro mexperience that a big cm will sound mean but will have no go for a a lake boat i would stay around 230 @.50 and around a540 lift on a 108 center this will give better lower end torque and lower hp range say 5k-5300 which would be good for an A or AB impeller on a bek type jet

[AZKC]

Sounds like I should go with their 278 grind its not quite as aggressive .564"/.566" 234*/237*
I'd like to spend a little time on the heads, I'm understand most of the porting stuff, rough on intake (mix up that fuel mix a little more) and smooth on the exhaust (get the crap out quicker) with out getting on a flow bench are their any good templates available or just match ports and go with that.
I have run an 850 cfm and it was a bit much driveability wise and not that economical on fuel.
(I can't even type that without LMAO, a jet boat thats economical)
I of course want it to bark alittle at idle but I dont think I can get it to twist much over 6g's. The pump is getting the once over also by Panther and I'm still contemplating their place diverter. And I do have that 150hp bottle setup sitting around but I wasn't ready to build the motor for that I was saving that for the stroker...
Thanks for the input
KC

[Omega21]

I bet if you searched the net a little you could find a page that would teach you how to build a flow bench from a shop vac & a ping pong ball in a clear tube... saw it on some go kart racing website.
Anyway, ran AZKC's motor on the computer. Couldn't come up with CompCams valvetiming events..as usual, no big surprise. I went with a lunati 31815 Oldsmobile profile & changed the lift to match the compcams numbers. Should be relatively close.
Anyway this it what the theoretical "Oldsmolet hybrid" camshaft looks like: 244/254 Duration, 108 C/L, .570 int, .575 Exh. Uses Lunati 31815 valvetiming.
These are the results, changes noted on each result.
-750 cfm, dual plane, stock w/big valve ported head, big headers:
peak HP=434 @ 5500, Peak tq =449 @ 4500.
Torque curve isn't really a curve...it's a plateau. Stays above 400 pounds from 2500-5500 RPM. HP is a gentle hill curve
-850 cfm, dual plane, big valve ported heads, big headers:
HP= 441 @ 6000, TQ= 453 @ 4500
-850 cfm, dual plane, big valve ported heads, big headers, same cam profile w/solid lifters:
HP= 466 @ 5500, TQ= 506 @ 4000
-850 cfm, dual plane, big valve ported heads, big headers, same cam profile w/roller lifters:
HP=491 @ 5500, TQ= 540 @ 3500, (plateau still there: TQ= 538 @ 4000, 531@4500)
-850 cfm, dual plane, big valve ported heads, big headers, same cam profile w/roller lifters, add 100 hp NOS:
HP= 591 @ 5500, TQ= 690 @ 3500
With the NOS, there are actually higher TQ numbers on the graph, but they're at like 760 #'s @ 2000 rpm..I'm not sure about anyone else, but I wouldn't turn the NOS on below 3500 for fear of it bending rods & breaking cranks..
And for fun:
1100 CFM, Tunnel ram, "Pro Stock ported" heads, 15:1 comp, big flippin lunati cam, and a 300 shot of NOS:
HP= 1047 @ 8500 RPM, TQ=987 @ 3500
Todd