Victor ported by Wilson manifolds and a 1050 dominator.

AFR 335's on a 540 in that rpm range are way too big. You'll never get any port velocity and if you're running a 1050 carb it makes things even worse. Only way to really make any power will be with a custom cam...short duration higher lift but that tends to be hard on valve train.

Well that is what I fell into so that is what I will be running. Agreed that port velocities will not be optimal but for what I paid for the whole package I can make it work... Also I am planning on running EFI at this point as I see considerable changes in altitude when I change locations ( greater than 4000' ). The leading candidate at this point is the holly single plane system.

Theres three different cams being talked about here.

139671 (525EFI cam)

236/244 114 LSA
.610/.632

Intake open 9
Intake closes 47
Exhaust open 61
Exhaust close 3

168741 also referred to as the "741" cam.

236/244 112 LSA
.610/.632

Intake open 11
Intake close 45
Exhaust open 59
Exhaust close 5

139021 (cam FBC25EL had)

234/242 112 LSA
.610/.632

Intake open 10
Intake close 44
Exhaust open 58
Exhaust close 4

The 525EFI cam, will hold on RPM a bit longer, than both the 741, and 021. Also, there is more to where the HP "peaks at", than just the camshaft. Cylinder head, induction , exhaust, can play a factor too.

I had a 741 crane in a 540, with iron merlin heads, dart single plane, and 1050 dominator. Peaked around 5600rpm on the dyno.

What are the specs on the heads on a 525 EFI?

Edelbrock 315 CC . Flow is not much better than a chevy iron rect port head.

Valve Lift .100" .200" .300" .400" .500" .600"
Intake 76 146 212 255 294 314 -
Exhaust 70 132 156 181 207 228

Edelbrock marine standard port height, nothing too special. Too lazy to look it up

I see, thanks!

Wonder what kind of increase you could get changing the 525Efi head to the dart pro 1 310 head? Any guess? Or should the 325 head be better?

IMO that's a poor excuse for building a poor combination given all the time and expense you'll have invested before you're done. You could easily sell the 335's and replace them with the right head for your combination. EVERYTHING will benefit from it especially if you're going to see altitude changes like that. A lazy induction makes an engine considerably more sensitive to those sorts of changes. JMO.

In my unprofessional opinion, forced induction would be a better way to more power than heads. Bang for buck a lot better but your XRs might not like them after a while. Or you can just leave it alone :cartman:

Blowers don't make sense since you need drives also. Was just curious what power was to be had at top end freshen up time in changing the heads....that's was all.

Seems hard to believe that with that kit it will make 620hp ish. Think so???

I can see getting a nice power increase over those edelbrocks. How much, IDK. But, those edelbrocks do leave something to be desired, when comparing them to a Dart, Brodix, AFR, Canfield, RHS, etc.

Probably 310s, you agree?

Confused. You mean the 310 dart? Not sure what you asking lol

Lol. Yes, in the kit, probably a dart 310. You agree? I think the 325 maybe too big. Thoughts?

That would be my guess too. A 310 Dart is a nice fit for a 502 Marine engine imo.

Dart does make the replacement heads for the merc 525, 600/700sci engines.

http://www.dartheads.com/products/cy...nder-head.html

Yes, that is what's in that kit you cited. Just think with a redline of 6k on a 500 inch engine the 325 would be too big. That's why I assumed the kit had a 310 in it.

Just for reference, back in 2005 I had a pair of 565cid naturally aspirated engines with 315 Cnc'd AFR heads, a mild hydraulic roller on a 115* lobe seps, 950cfm Holley carb, 9.5:1 comp ratio,....

again,...little ol' 315 cnc'd AFR heads on some BIG AZZ 565cid engines...

...with the props I had the engines ran up to 5600rpm with full tanks of fuel in my 32' AT and would set you back in the seat when you pegged the throttles from 4000rpm....my buddy has a 32' AT with 556cid engines with 871 superchargers and he could not pull away/out accelerate me, or beat me at top RPM with his supercharged engines that made 750+hp.

315's on a 565 at that rpm are a nice combination!

Yes, I would undoubtabey have to agree.

Also, I think it was back in 2006 in my 32' AT, that I was running along the side of a 36' Apache with a stepped hull up at Hardy Dam,....and if I remember correctly, he was supposedly running a pair of 800+hp Vortec supercharged engines...we ran full throttle side by side for a minimum of about 7 minutes...I squeaked him by a hair. My point is, even if he "squeaked" me by a hair, my boat was a runner with those AFR 315cc heads on naturally aspirated 565cid's and very mild hydraulic roller cams that would idle sweetly at 650-700rpm in Neutral. Those freakin' engines were/are some runners with some really sweet docking manners.

I will add that the engines were built by Dave Wesseldyk of Wesco Racing Engines and the head and cam combination were provided by Bob Madara of Marine Kinetics. Excellent and very intelligent guys to work with.

Probably "blue moon" the 36 apache ? That boat runs well. He used to tak that thing everywhere, lots and lots of hours on it. I think ben at precision built the engines ?

I remember reading about your 565 builds back then. Didnt Jim valako do some work on the heads ?

It was shortly after that Bob Madera did a hyd roller cam for my afr headed 540 that made 657hp with blower belt off at only 8.4-1 with a highly modified 502 mpi intake and throttle body/315 AFR'S, 1115 hp on 80% 92 20%/110 race gas, 1057hp on straight 92 octane with pulley I ran 95% of the time, I had raced you back when I had my 950 hp motor in the Baja several times, MEMORY'S!! That 657 pull was with lightweight oil, it was in high 640's with the 20w50 in it, no water pump or accesorys so in boat Im sure it was a little lower. I tried running the thinner oil in boat and even with large cooler and 14 qt pan the pressure made me nervous at 40 ish psi hot! Smitty

Those 315 heads flow good. My buddy joes 522ci with 315 afrs, 10-71 littlefields, made 1036hp with 10lbs boost this past spring, and great torque.

I wish I could go back to this time last year.... ugh

Yes Joe, it was "Blue Moon"...from what I always knew of Steve (the owner), he always built his own engines himself, but I think he had Ben at Precision Power dyno them or help him in some way.

It was when I had my 565cid engines built by Dave W back in 2005 that I had installed the 315cc AFR's that I had gotten from Bob M. It was the couple years prior to 2005 that I had some Dart Pro-1 310cc as cast heads that he had ported and those were on my 540cid engines before turning them into the 565cid's. I sold those Dart Pro-1's to "Tinkerer"

I could not modify or edit my previous post,...I meant to say, that Jim Valako ported those Dart Pro-1 310cc heads for me when my engines were 540cid...it was before I turned my engines into 565cid in 2005.

My motor is 612/634,236/244,110.5
540 9.6, iron eagle 320 bowl blend after concentric valve job. Dan davinci 940 carb. 34 degrees. Afr in boat 12.6 ish. 1.7 rocker s stainless. Comp lifters. [ATTACH=CONFIG]548149[/ATTACH]
On pump gas. On motor no blower.

that's crazy, cam is also MUCH less then mine, I plan to dyno and see where I am at, but my 540's are similar with much bigger cam, boats speeds did not change, over my 600 hp engines. what boat are these in? drives and speed?

I am really trying to narrow down my setup and what to change if anything..

maybe your heads are to big and your cam is to big, killing your upper midrange torque?

540 CI AFR325's cam is 241/246 681/663 112, 9.6:1 compression single plane with 1050 carbs (4150) style, did not dyno but results in boat were no gains, so I really and trying to see whats wrong with the combo, I was assured easily 680++ hp and TQ, my old ones were 598 hp and 663TQ so I am baffled.. I am just getting specs from different combos from guys that seemed like success...

Nice numbers, what exhaust are you running? Dry tails?

1987 sonic 36 ss. Trs drives 25 mirage plus , davis distributor, stainles marine exhaust wet, 76 at 5300. Crossover, blocked bypass, no thermostat on water, 15 / 18 psi, water temp 100 / 120 max, been 83 with 4 blade hyd q4 s 27p , but rpm 4700, broke prop shaft and housing.
Uses 60 gallons on 78 mile non stop 3/4 full the whole way. Best thing motors were cheap and dont run hot or so much as tick. 7/8 fuel pressure. Holley pump nmechanical. The carbs were 1200 each but well worth it

No wet , stainless marine. Not cheap but imho not power robbers

I got a 2 inch spacer as well merc 500 bulldog flame supressor air filter thing was worth 10 more hp believe that ****

How thick is the head gasket ? Builder might have fuk d you on compression I'm that way just cause I been there.
[ATTACH=CONFIG]548152[/ATTACH]
Original dyno sheet bro. All I did was lifters and took out 060 head gasket and comp was like 7.6. Picked up 130 +

What drives you runnin

Hey Tim.
Is that compression ratio a theoretical or an actual measured number? It doesn't take much area to change the ratio.
I'm not trying to bust your balls, but maybe your down on compression.
You said your cylinder PSI was on the lower side, no?

Going from a .060 head gasket to a .040 head gasket changes the compression 3/10ths of one point on a typical 540, if you were at 7.6-1 you would now be at 7.9-1 so IF your at 9.6-1 now you were actually at 9.3-1 before, the 3/10ths of one point is worth about: 5 to 10 hp MAX at the 675 hp level, not 130 so you had other issues you overcame such as the lifters you mention
"Wallace racing": your old Compression Ratio of 9.3-1 and HP of 675 is now calculated
as a Compression Ratio of 9.6-1 and 680.92 Horsepower.
http://wallaceracing.com/hp-cr-chg.php