SB

I have only looked at these two so far, and I was WTF with how low the power was..then noticed 'Wheel HP' and 'Wheel Torque.' Can that be taken out ? Of all if they all have it ?

SB

Another question, are the averages taken from every 500rpm figure shown, or is it done every 100 rpm like a normal dyno test?

sutphen 30

you said this was most power at 6k,,right.

sutphen 30

the ole 741 cam,,that junky 20yr old tech wins,,now who would have thought.

SB

Correction factor was way off. And the carb was way off too.

Full Force

So in my thread every single person said my cams were WAY too small, now the 741 cam is best that was smaller then what I got? I don't get it...

sutphen 30

uf course I'd never build an n/a engine w/ 8,4-1,,hell,not even in a blower package,unless I;m adding 15lbs of boost.

sutphen 30

I didn't.

Black Baja

If you want to spin the motor to 6,000 IN the BOAT. You need to look at the numbers from 5,000 to 6,000 the 741 isn't going to make it to 6,000 it will stop dead in it track right where torque and horsepower cross. Actually if you want to spin 6,000 in the boat the Howard cam you choose looks to be the best.

MILD THUNDER

.

Now, here's the catch. As we know, its a combination of parts, that makes power. Its not just a cam, not just a head, not just an intake, and so on. Modeling this build, the options for single planes, are STD flow, high flow, and max flow. I chose the high flow intake for the test. Now, going to a "max" flow intake, which would resemble say, something maybe like a ported super victor, or something along those lines, the power went up.

He has a 1050 CFM 4150 style carb. I used 1050CFM for the test. Coupling the "max" flow intake, to an 1150 cfm carb, again, the power went up. The HP peak rpm did a little bit as well. The big cams werent showing big gains up top, probably because, the engine was simply running out of components to compliment the larger cams. But, when you changed those components, the gains from a larger cam, become more noticeable, and begin to offset, what they give up in the lower rpm torque department.

Basically, a 741 cammed 540 thats making 647HP with a mediocre intake, mediocre carb, and 9.5:1 static, can be transformed into an engine that now makes, close to 750hp, at 6500RPM, with the big cam, that only made 678hp with the mediocre characters in the cast. Now we're making some steam in the upper powerband.

Of course, there's always going to be a trade off with big cams. What you gain up top, you lose down low. That 6500RPM 750HP engine, isn't going to make the torque at low rpm/midrange, that the 5500rpm small cam is going to .

My general opinion on this stuff, is a cam is only a small part of the combination. The heads, the intake, the carb, the compression, the EXHAUST, and the tune, all play an equally important role.

Generally speaking from what I've seen between actual dyno's, and computer simulators, is exhaust a major player on these marine BBC's. Out of all those cam swaps, nothing HUGE was gained. But, simply switching from a large tube header, to a small header, The change is significant . The bigger headers on this build , make significantly more torque, and peak power, than a smaller header.