powerband...

[nos1967]

so ive heard differently from every person i ask. in a jet boat do you want more low end torque or mid to high end hp to get er done. seems like a jet revs fast so mid to upper power would work best, but people keep telling me dont worry about upper end at all just go for torque. im looking at a 4x4/marine cam from comp cams that has a power band of 2000-6200 and makes great torque starting at 2000 rpm and makes power all the way to 6 grand. my highest rpm's will be 5000, maybe 5200. so seems like that cam will make great power at my rpm range to get my highest rpm level possible....any help would be great. thanks -scott
this is for a 327 in a 16' tahiti btw

[Squirtin Thunder]

I would concider a Comp Xtreame Marine 278 cam !!!

[SmokinLowriderSS]

I think you have a pretty decent grasp of it. The trick is really (in my opinion) the mid-range torque to make sure you are "ahead" of the impeller power consumption curve. I've seen some motors with really powerful builds at high RPM's but didn't have enough torque arround the 3-5K range to get even close to their max horse power RPM. I would try to select a cam to peak your HP at or a bit above your expected running RPM, and build all the torque you can, especially with a small-block.
I do not have nearly enough experience with small-blocks to shoot a cam for advice, so I will defer to Thunder. I'm sure the one he has advised would be a solid choice among the many available.

[BigBlockBaja]

I would concider a Comp Xtreame Marine 278 cam !!!
280H is a nice cam to consider also. I have been running one in my ride for a season now and its a good all around cam.

[nos1967]

I would concider a Comp Xtreame Marine 278 cam !!!
that is the exact cam ive been looking at for weeks, its official thats my new cam haha. im getting the whole kit, all i need now are rockers and pushrods. gonna get the comp cams roller tip steel rockers and was wondering if i could use my stock push rods with the comp cam kit? or if i should just replace them now and which ones should i get...

[jtmarten]

Run several different cams through desktop dyno. It'll show you torque and hp curves that are really helpful in choosing a cam.

[centerhill condor]

you're getting the bread so don't forget the butter... new pushrods...pete jackson gear drives are much more accurate than a chain.. just a thought.

[nos1967]

i am on a budget...which is maxed out now haha. ive got everything i need now. one more question, what gaskets should i run? i was thinking the fel-pro high performance kit built for medium-high revs work work as well as marine gaskets....or should i definitely go with marine gaskets. i will be working with 10.3-1 compression so a thick gasket would help bring the comp down, which would be nice.

[SmokinLowriderSS]

I'm running fel-pro auto gaskets. no problems.

[Wicked Performance Boats]

you're getting the bread so don't forget the butter... new pushrods...pete jackson gear drives are much more accurate than a chain.. just a thought.
A double roller chain setup is a better choice for a jetboat in my opinion. As the chain gets older it stretches a little which helps retard the cam timing at higher rpm,[which is better]. But if you don't even degree the camshaft in, don't worry about. I reccomend installing the cam, 4 degrees advanced. Imo Budlight

[SmokinLowriderSS]

Last winters rebuild installed a Comp Cams double roller, billet gears, 9 keyway cut, with block bearing installed setup, $100. Went on straight up as DuaneHTP has his Isky cams ground 4deg advanced. He told me over the years a lot of DIY'ers like me tended to not get it degreed 4* advanced as he reccomended, so he decided to just have them cut it advanced & install it straight up. Simpler for me :cool: .
I think Cloyes actually makes it which won't please some of people, but is working fine on mine so far, I'm happy.

[Wicked Performance Boats]

That was smart of Duane to do. I've found most DIY don't degree camshafts. Duanes idea helps fix lazy engine assemblers. But the true purpose of degreeing a camshaft in is: to determine where the camshaft is and what you need to do to get it where you want it. What Duanes trying to do is help DIY make their motor perform better. It's not hard to do, takes about an hour, and costs about $100-$150 to do. Then you will know for sure. Budlight Ps. Have you ever heard of 2 identical cars straight from the factory? One is faster than the other? I believe it's where the camshaft is from machining. or the crankkey is cut.

[SmokinLowriderSS]

Yea, Duane told me he got tired of people coming back with complaints, and it would turn out that they had it mis-degreed, or retarded 4* (so was 8* from desired). It sure pulls hard for me, idles well (lopey, a head turner), snaps right off idle, smooth midrange, doesn't lay down on top, just pulls till the pump says "no more". I'm happy! Will see how it likes the headers this spring. :idea:
Seen it mostly on identical bikes myself. One got an advantageous "stack-up" of mfg tolerances (including cam degree and such), the other was "normal" but didn't run as well. Both were new & unmodified, exception being headerd & carb adjustment to headers.