i base that on my engine...

merlin2 540 ci block
9/4/1 comp
canfiled 310 cnc'd chamber heads
merlin intake
950 hp carb
crane 731 cam 587/610
stainless marine manifolds


dynoed with flame arrestor, sea pump, alternator

here's the dyno sheet ,

if i had cmi's , spacer, dominator, and a custom cam the #'s may be somewhat larger , but i don't belive that the above engine could gain 119 more hp total.


ie "giving dyno".

Open,when you compare head flow #'s the afr315's flow 16%more at .400 lift( averaging the intake/exhaust flow difference) and 11.3% at .600 lift,lets say on average they outflow canfields by 13.65%,2 identical built motors with each brand head could have a 13.65% power difference. 600 ft lbs tq X 13.65 =82 ft lbs more from cylinder heads alone. Now,I am not picking sides here for a fight I'm just pointing out a few facts I know to be true being I have a 540 also with afr 315's and have studied these combos ALOT . Looking at both your dyno sheets I will point out something that I don't like on either one,starting with yours open 72-your tq peak was at only 3700 rpm's and proceeded to drop from there,something in your cam/head/carburation choice held you back at that rpm, you could have done this on purpose to keep your peak hp around 5200,I don't know but I do know if your top end choices had moved your tq peak closer to 4400/hp peak to 5600-5800 your numbers would be more sunstantial.On the other end of the spectrum I see check 454's tq peak at 4900 rpm's and his hp is still climbing at 5800-5900 which indicates he gave up some some drivability and lower tq to achieve top end hp that is more "race like" and less pleasure boat friendly. If he had a slightly smaller cam and had peaked at 4400-4600 his numbers would be about 30 hp less and had more usable tq. RLW ran into this on his na motor also,it made outstanding topend numbers at the exspense of midrange. These are just my observations,not trying to make enemys here,Smitty

Let's see if this works.

no , not trying to down anyone . just a observation , yes , i was not looking for top end hp. more low end than anything , old cigarettes are not light by any means. i enjoy more of on/off throttle in crushing waves, if i wanna go fast , i have the wrong boat..my goal was to have 600lbs thorugh useable wot rpm range.


(both combo's are low on comp needed to make better power)

smitty , i read your posts on here , u know your chit..

i'm not knocking or looking for argument ,and i'm no engine builder,you calculated difference in head flow, i understand that a 1050 , cmi's, little different cam , will make some added hp. but with 13.65% in flow i still don't see 119hp?

i also understand that many people dyno with no accessories and use the headers at the dyno room = bigger #'s.. but that's not what's in the bilge.

OPEN 72 more cam &more cyl head = more power. I would look at some head work and a bigger cam for your 540.
650 - 700 hp is not out of reach. Compression ratio could also be increased and still run pump gas.

I also understand that many people dyno with no accessories and use the headers at the dyno room = bigger #'s.. but that's not what's in the bilge.

True True.

Open,
Are you pushing that Cig with one 540? I've always been facinated with the old Cig 28's like yours.
Russ

Maybe I should have stated that when my motor was on the dyno, it had no accessories and dyno headers. Maybe I am wrong, but I dont see a big difference between dyno and CMI headers. There will be power loss with the accessories, dont know exactly how much. Not 100 h.p. for sure. I can say that I built this motor myself, I know exactly what is in there. I can also say with confidence that it was dynoed at a very reputable engine shop here on Long Island, New York. I wont speculate as to what type of dyno they have , because I dont know. For those of you who are from the area and may know of Lab Machine in Lindenhurst, this motor was dynoed there by Lee.

Russ,
Is that graph a comparison of my motor to yours? It looks like it is to me. I remember yours making more power than mine.

Vinny

Zimm17, Here is my dyno. runs 80+ @5,600rpm all day. With more head work and different cam it will run faster. I'll be switching to a larger pitch prop in the spring. Talk to Mike at http://www.roccardmarineengines.com/

will be , i had a 420hp before ,did 54-58 , not too bad . the plus - in this hull - doesn't have all of that deck - being that it's "open". i have not installed the engine, if you look at the date of the dyno sheet it was friday before the storm f'd everything up down here . i will start a thread when i get back to it. i'm dealing with our first baby 4.5 months and is whipping our azzes..on top of our small town turning into new orleans overnight , or so it seems..


checkmate-
i am not knocking your engine , or you building it yourself, or the parts in it.
dyno headers do give best #'s. throw on the raw pump , arrestor with proper amount of mesh , alternator ,etc and you start losing #'s pretty fast. that's all. hence "giving".


smitty , do you have a break down of how much power those parts rob?

down here engines are dynoed with exhaust and everything else to make it work ,giving totally different #'s. what's in the bilge is in the dyno room for each specific engine.

no offense intended..

i belive that the starter of the thread can get 550hp out of his 454 personally. alot of good threads on OSO on how to get that done with 454 cubes..

open72,
No offense taken, we are just discussing things here. The purpose of coming to this site is to learn something.