Scott

I keep seeing this number come up all over the place 741 and have to wonder about the application of this cam.

This is NOT to start a negative debate I seriously don't understand and would like to hear some input!

It seems at though no matter what a guy is doing to his motors when he asks for a good cam profile the 741 comes up. I would think with different heads and carbs along with blower vs. no blower not to mention rev limiters that there would be better or should I say less aggressive choices (sometimes more is not better).

I thought compression and head flow had a lot to do with choices I also thought blower motors liked a less aggressive profile.
I was also wondering about rev limiter or module limitations why would someone want a cam that makes power up above their limitations.

I really want to understand all this that is why I am asking all of these questions.

Thanks, Looking forward to some answers






731 741 761

Cord

Well, actually the 741 isn't all that agressive of a cam. Compare the 741 that we use in a 540 to a roller cam that is used in a street 454 and you'll see what I mean. The only exception is in lift. The marine cam has a ton of it. Because the cam is short on duration, has a wide separation, and high lift the cam is excellent for a blower. It's also good for n/a marine use as the same properties result in less reversion with some sembelance of power. Short of really doing some dyno work and having cams custom ground, it's your best bet for a large displacement motor. Any more duration and you'll be spinning the motor too hard and running into lifter problems. Anything less and you'll be losing power.

bobby daniels

I'VE spent a fortune trying different cams and unless you take everything you said into consideration and do a custom grind the se two cams for hyd. rollers are great all purpose cams !!!
Sure we have cams that work better but again you need to be very specefic . We have a hyd cutom roller that truly makes 40+ more H.P. than the 741 min. put it custom and tons of hrs. in devlopment work.
Blowers let you get away with a smaller cam but they do like aggresssive profiles ,,,turbo take a different profile than a blown
app.

Yes you need to do it right get your ECU rpm changed and recalabrated this will really help ,It really helps if you send the dyno sheet with the ecu to be changed ,,

This could go forever hope this little bit helps :

Johno

There are 2 741's. 168741 & a 139741...whats the big difference?
I have a 509 motor Gen 6 that I want install the 139741. Is this the correct part # for a Gen 6 motor. Any idea the HP you would get on HP 500 bored .30 over with the correct 741?
Thanks John

Scott

Johno

168741 is for a gen 6 The other cam has a different snout and uses a button to keep it in place. The Gen 6 has a plate in the front that holds it in. I'm sure there must be a more tech way of saying this but I'm hoping you get the point.

Scott

bobby daniels,

This is kind of what I had thought but it still supprises me it can be so general purpose. I understand all the time that must go into the trial and error process and the well kept secrets$$. I guess it just bothers me when I see some guy "Saying ya dude I got the 741 and it sounds so cool at idle man" and I know they are barely turning 4800 RPM's. I know this is a exageration but I hope you guys understand my point and of course the confusion.

Please keep the info coming I would like to learn as much as possible.

What about guys with stock limiters or the wrong prop combo would it be safe to assume that the 741 would be much better in a motor spinning around 5500 and up or am I wrong in thinking this way.

KAAMA

Johno,

DanB, had a 9:1 comp ratio, 509" naturally aspirated engine with an Air-Gap intake manifold, NON-ported World Products cast iron heads (308cc I think)950cfm Holley carb that had a 741 cam and it made 563hp @5500rpm with dyno headers on Tyler Crocket's dyno. Dan ran the boat with Lightening headers.

BTW, it made 620ft lbs of torque @3400rpm

bobby daniels

Scott I fully understand where your coming from !! Cams are tuff at first !!!
The 741 like I was saying on the thread on here now WEIAND177
something or other ,,was to big for the guys 454 ,,he needed a 731 due to having a 454 not 502 or bigger ,,it depends it just so
happens most boat owners aren't interested in 110% power so a good general purpose cam will work and most boats have the same basic merc .motors to recomend for ,,
but it can get tough ,

your right the 741 would do better in the 5 to 5500 range in a 502 and bigger and 55 up on a 454 ,so your on the right track ,

Let me know I'll help anyway I can ,,p.m.,,,,me or what ever