KAAMA

iTrader: (1)

At least one person who would be one of the best for cam selection is Bob Madara "RMbuilder" of Marine Kinetics---he will get the right cam for you and your application. Bob has helped many on this forum with proper cam selection.

By the way, Dave from WESCO orders pretty much ALL his cams from Bob Madara for the engines he builds....and he builds some top notch marine engines and he isn't too proud or egotistical to ask for cam advice. He keeps ordering them from Bob from one engine project to another....must be he likes what Bob provides.

Now the thing is, is that your engine builder knows what it takes to build an marine hi-perf engine properly. That might be the next thing I would be concerned with.

Hope it all goes well for you. Phone numbers are below

Whiteknuckle

nocigerette,
Do what Kaama suggested and call Marine Kinetics, aka Bob Madera, 586-772-2395. Tell him about the bind that you are in. He may or may not be able to regrind that existing cam. Make sure you have all the particulairs on hand about your engine, boat, intended use etc. He needs information. He will help get you where you want to be. He did a great job with my cam selection, and he is a great person. Tell Bob Whiteknuckle said "hello".

KAAMA

iTrader: (1)

You start drinking at 10am??? Don't know who's phone number you posted above, but it isn't Bob's. Anywaym his correct phone number is 585-654-8583.

rmbuilder

Nocigarette,
The cam your engine builder has selected for your application is a Comp Cams:
Part # 11-749-14
Grind # 47S 313R10

As everyone has stated, the cam is mismatched to your components. With a 9.5:1 SCR and the late IVO of this lobe you will be seeing very low cylinder pressure killing off virtually all your mid-range TQ/power. This profile, with 540 displacement, will make peak TQ ~ 5800 RPM and peak power ~ 6900 RPM. If you prop for 5800 RPM, this places your WOT at approx. peak TQ, negating the fat curve from peak TQ to peak power.

Idle quality will suffer due to the 100º overlap, making the boat difficult around the dock and hard on parts during drive engagement. The recommended spring package for this cam is the Comp 948/26082 Hi-Tech Drag triple spring, set up @ 332# @ 2.100” seat, with an open force of 949# @ 1.200” 686# rate. Those numbers are also a bit of a red flag regarding pushrods and lifers. Even if you do not RPM the motors these lobes will require serious spring to control a 150-gram valve. It would be impossible to put any cycle values on the valve train components due to the (NC) intake and (–3) exhaust lobes being run at prolonged RPM.

In regards to regrinding the cam I would suggest you contact Comp Cams directly for the most accurate answer. It is a 4/7 swap on a billet core, however without knowing the core/base circle sizes, it is impossible to know exactly what lobes can be put onto this core. 800.999.0853, ask for Chris Padgitt.
Hope this helps.
Bob

nocigarette

i cant say enough good about you guys thanks a lot.................

nocigarette

Ok.....You guys will think i am crazy but i ran that cam this year....First let me say that the boat ran 3mph faster than last year...The cam never broke any valve train parts.....With that being said now i have a huge tuning problem with the carb, i can not get it rite on top end or mid range but it idles like a kitten................

My question is ,,,,,,,,should i leave the cam in or should i due a swap while the motor is out and in my garage for the winter.......( carberator is going to nickerson )

I am not trying to sound arrogant about the cam working, i am still looking for advice.....Thanks a lot guys

racinfever

It may have run even faster with the correct cam, tell us your final engine combo, performance info Rpm top speed & how much prop you turned. And why you are pulling the motor after one season ?

nocigarette

I pulled the motor because i am going to add a thermostate controlled oil system and wanted to check the mains and rod bearings...Unlike a lot of guys on here i use my boat every other day .....I put almost a hundred hours on a year....So if ya are trying to imply something DON'T......Read the posts about the rebuilding of my boat.....I am over anal about my boat and i check everything every year......If you are going to give advice i can use then post if not then due like your mom told ya growing up ( If you dont have anything nice to say don't say anything at all)

racinfever

I'm sorry if you misunderstood my questions! I wasn't implying anything negative I was just trying to further expand on the discussion as to what cam may be better for your application should you decide to change it. Afterall, you avatar says 1974 magnum sport with too big of a cam.
I hope this clears things up!!

nocigarette

It is hard to exspress how ya feel while typing.....No sweat i'm sorry if i got carried away....