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-   -   Off the shelf Cam- Dyno results (https://www.offshoreonly.com/forums/general-q/338342-off-shelf-cam-dyno-results.html)

Sonic30ss 06-16-2016 07:04 PM


Originally Posted by getrdunn (Post 4450452)
Nice respectable build especially considering out of the box 308's. Job well done. Awesome torque all the way through. Thumbs to you. Now just curious as to your decision with your cam choice over the 741 being so close yet different? More than like the peak rpm/hp. Regardless great choice.

Did you end up more? Less? Or about what you aiming for?

As far as Comp vs. Crane.....I like the 114 LSA of the Comp, I thought it might get me what I was looking for- broad flat torque and the exhaust has a long way to travel, especially the inboard pipes, so also trying to limit chance for reversion.

Fact is I ended up exactly where I wanted to be; 640 was my hp goal all in below 5400. Torque- I didn't have a number in mind, only as much as possible starting at 3000 and continuing WITH NO DIP for as long as possible. Truthfully I'm surprised by the tabletop we ended up with and super happy! Overall boat performance goal is 40 mph @ 3500 rpm.....whatever I get on top is a bonus, guesstimating 57-60
I feel this build is about all the parts working together, the cam may be the conductor but the carb, intake and heads have a lot to do with the success too

I've over cammed many a street/strip engine back in the day.. old .590/322 Mopar solid lifter cam in a 440 with a rat roaster 6 pac intake.... thing was a bear from 4000-7200, but drop the clutch at 3200 and it would stop pulling fuel, fall on its face for a second, get a little air speed back and run like a freight train thru the lights, it was fun but taught me some lessons about what I absolutely don't need in a 15-17K lb boat ;)

SB 06-16-2016 07:08 PM


Originally Posted by Sonic30ss (Post 4450509)
it was fun but taught me some lessons

Yes. Ditch Mopar and build 500+cid BBC's. Hah !

Sonic30ss 06-16-2016 07:17 PM


Originally Posted by SB (Post 4450510)
Yes. Ditch Mopar and build 500+cid BBC's. Hah !

Easy turbo!!! The 432'' Hemi I had in that thing would eat these 540s for lunch!...however it's fun on the dark side these old porcupine heads are better than our wedge heads :)

Aqua Banshee 06-16-2016 07:45 PM

Speed wise your guess is where I was guessing also


Maybe the hull will free up and get above 60

I agree also on the exhuast. It's still a cruiser, so lots of idle time

getrdunn 06-16-2016 08:03 PM

Well thanks for your thread. That same combo would be a great reliable package in just about any boat. You could not have done a better job for your boat though. Just all around good builds and so close to advertised rpm range as advertised.

mmb 06-20-2016 10:51 AM


Originally Posted by Full Force (Post 4450155)
Looks good to me! Man I love my "custom recipe" even more now... Good job!



Originally Posted by mmb (Post 4401408)
But Yes if I was doing that cam with bob I would have probably kept it around 232/236 .650 lift..... (From the top of my head without researching all your data) I have always made better power going to the smaller side of the cam than the larger for the application.

No matter how you feel about me I am/was trying to help you!!

MILD THUNDER 06-20-2016 11:59 AM

700hp wasnt , or isnt happening, with a 232* duration cam in a 540.

mmb 06-20-2016 01:31 PM

Simple!!

mmb 06-20-2016 01:42 PM

When a flow bench and dyno go scooting across the lake I will pay attention. His boat slowed down with parts that should have made more real power and it has nothing to do with .050" lift.

MILD THUNDER 06-20-2016 02:00 PM


Originally Posted by mmb (Post 4451439)
When a flow bench and dyno go scooting across the lake I will pay attention. His boat slowed down with parts that should have made more real power and it has nothing to do with .050" lift.

The problem is , he had a 565ci, and went to a 540ci. He dropped 25 cubic inches. He was sold on afr heads being so much better than the pro comp heads he had, that the head flow and cam would easily make up for the 25ci loss. He isnt going faster, and the dyno showed why he wasnt . The engine simply isnt making 100hp more than the 600hp 565s he had, although they were supposed to make the 700hp.

That 241/246 680 lift cam was dead by 5400. Its no surprise to me why his boat isnt going faster.

Ive seen a couple of these custom marine kinetics camshafts get yanked out, some had 50 hours on them, lobes beat to chit, valve seats pounded into the heads, as well as back to back tested against other camshafts, and simply lose there as well. So, they werent winning in the reliabilty, or power department. And these engines were built by pros, not some diy'er slapping stuff together.

I guess when you believe that a head has the best exhaust port in the industry, based on marketing claims instead of real world flow data, and cam the engine around that concept, its no surprise the results are less than expected. But hey, the guy who worked for roush, dart, and spent a good majority of his life modifying and improving cylinder heads, is called an idiot, by a guy who has never cut a valve seat in his life. Whatever sells parts I guess!


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