stock cammed 310/454 + aluminum heads/intake= ??

[HTRDLNCN]

I have the peanut headed 310/454 , I want to put a set of
ovalport aluminum heads (ebrock or similiar) and intake (ebrock rpm)
,,the 454 replaced a 350 so now my boat is rear heavy,trying to shave
weight as well,I already have the GLM aluminum exhaust manifolds with
4" thru hulls. I do not want to mess with the cam ..
My standard boating is about 85% of the time at 2500-3000rpm
( 26-32mph) 14% of the time at (3500-3800) roughly 40-44mph ,
and maybe 1% WOT 4200-4400rpm 54-57mph..
What will the heads and intake gain me power wise?
From what I can gather the old 330hp engines had
the big ovalports so I cant see the heads making that
much more power, the stock intake is pretty low profile
so replacing that may help.
I am thinking maybe getting 340-350hp with an increase in rpm??
Enough to push me into the 60s?

[Beer-30]

I think it would be an excellent motor with the Marine-O heads (oval port). As it says, match the cam and intake. I would bet you would be in the 440-450 hp range quite easily. Probably higher, but I am being on the conservative side. Your bottom end can handle that much.
From Edelbrock:
MARINE-DUTY PERFORMER RPM 454-O AND 454-R
Heavy-duty, 1.89" Inconel exhaust valves provide added durability for marine applications
Hard anodized to protect the aluminum in the harsh marine environment
Sold with valves only to allow for valve spring choices
Match with an Edelbrock Performer RPM manifold, Performer Series 750 cfm marine carb and Performer RPM cam for proven performance
Smaller-than-stock 11/32" valve stems promote excellent flow and lighter valve weight

[HTRDLNCN]

As I stated I will not change the cam.
It would be heads+intake+carb only...
1. I dont like rumpy or high idle
2. I want to keep the rev range down
3. I have an Alpha drive which definately wont like a rumpy or high idle.
I currently have her idling at 550-600rpm so it shifts into gear like butter.
4. I dont want to deal with water reversion problems with the manifolds.
I guess my question would be will I get 40-50hp from just the heads+intake ?

[victorfb]

your biggest performance gain would be the decrease in weight which may gain you some rpm. without changing the cam you probably wont gain much in torque/HP. allthough the smaller CCed heads will give you some added power potential by increasing the compression ratio. for the investment you plan to make i would highly suggest changing the cam to match the heads and intake. you dont have to have a huge lopy cam. just one that will take advantage of the heads.

[Beer-30]

Valve size plays a big role in airflow, so just the fact that the new heads have the large valves will probably give you the 40-50 you are looking for.
You definitely will not be getting your moneys worth out of the heads, though.
But, once the heads are on, they are on. You could always change the cam later if you wanted more, but the heads would already be complete.
You could also go with a "Performer" intake and cam as opposed to the recommended "Performer RPM" setup. No rumpity. Good bottom end. A great happy-medium between stock and the RPM setup. It's just hard to see someone tear that far into a motor and not freshen the cam and timing chain.

[HTRDLNCN]

Thats an idea..
I compared the two and it seems like the performer is pretty close to
the stock profile so it should idle fine at low rpm it seems.
Mercruiser310 214° 218° 461 479
Edelbrock2162 218° 228° 500 500

[hotbo]

ive never heard of anyone wanting to go to all that work for nothing?:jawdrop: if you do not cahnge the cam profile you will likely gain nothing but weight lose!when you go to a better flowing setup you need a better cam profile to take full agvantage of it,other wise why do it?i guess what im saying is your already there throw a different cam in there.;) you can go with a nice mild cam which will not affect idle and gain plenty of horspower and take advantage of your new freer flowing intake setup.stay in the mid to high 220s to low 230s @.050 duration wont change idle that much.what i mean by much is it wont shake the boat and you can still idle around 600-700rpm with no problem.comp makes a extreme energy marine profile that sounds good-218-224-505-515,another one is222-226-525-525.either one of these would be good still have good idle and pull good vacum and notice alittle more power.but then again its your boat and you make the desecions:D

[HTRDLNCN]

Only reason I have been thinking of this is because everyone
always tells me how much the peanut port heads are holding my motor back. On theother hand I have read all the bad stories of people putting cams in with stock type manifolds and putting water in the engine especially
in situations like mine where they had to have a low idle speed. .
Thats what my thinking was..
:) :)

[Beer-30]

But, as mentioned by a few, it would almost be useless to just change the heads. Right now, the peanuts are flowing what the cam will provide. Get rid of the peanuts and the cam is still providing peanut flow. The cam will now become your power/efficiency barrier.

[hotbo]

just remember when choosing a cam lift makes torque not duration:) i looked at the performer cam and it would do good for your application imo:D i like the compxm262h part#11-232-3 better b/c of the slightly higher lift.but what ever you do go ahead and get rid of that ole tired stock 330hp cam there lobe seperation is usaullyon the 114 scale which is way tired.anyway i wish you luck and its always exciting to cahnge stuff.:)

[cfm]

As mentioned above, but with a little more detail, your cam is an underachiever even with the stock peanuts.
Mercruiser BBC Flat Tappet Cams
Standard Flat Tappet (oval heads)
Merc#431-4734 / GM#3904359
.004” 287*, 302
.006” 278*, 289
.050” 214*, 218*
.200” 111*, 119*
Valve lift with 1.7 .460” , .480”
ICL 110 ATDC
ECL 118 BTDC
114 LSA
=======================
Will you get 20hp with Eddy aluminum heads and intake ? Sure. More ? Doubtful. They do have smaller combustion chambers (110 vs your 118 or so) and will let it breath over 4k where your stock intake/heads are sinking fast.
You don't have to get a 'big' cam, just something more modern.
MPH ? Not sure. Need to know your present mph, prop, boat. weight, etc to make a 'maybe' guess at it.

[SmokinLowriderSS]

As I stated I will not change the cam.
It would be heads+intake+carb only...
1. I dont like rumpy or high idle
2. I want to keep the rev range down
3. I have an Alpha drive which definately wont like a rumpy or high idle.
I currently have her idling at 550-600rpm so it shifts into gear like butter.
4. I dont want to deal with water reversion problems with the manifolds.
I guess my question would be will I get 40-50hp from just the heads+intake ?
So, my 800RPM idle, with my .565" lift, 280* duration, only mildly rumpy cam, with no water reversion trouble from jacketed through transom headers is out of the question.
OK.
If you have a cam anywhere similar to the .461/.480" x 262/274* that came out of my oval-port (supposedly 330HP, really 280 to 290HP) 454, you are wasting the head money looking for HP.
You may gain a few HP from the heads, and maybe a few more from the intake, but a cam like mine was will be choking any capability you find.
I think you'll be lucky to find 25HP.
Waste of aluminum head $$$.
They'll sure look purdy tho. :)

[ck7684]

Why not just build up the smallblock?? Are you looking for power or just weight savings?? Throw some alum heads on the 350 and build that for power. Spending the money on alum heads and sticking with that cam just makes no sense...

[HTRDLNCN]

so cam change is a given then for the heads/intake to be worth it..
next question:
does my engine have a roller or standard cam,
how would I know without taking it apart?
I do know it doesnt have a provision for a mechanical fuel pump
(runs fuel pump off the Bravo raw water pump drive) and I think
it was one of the last years with a carb for the standard 454.

[hotbo]

only way i would be able to tell is pull intake then you know.hope it is,be real nice if so.smokin's awful proud of his cam as you can tell:) well for one thing your boat is not a jet and you put yours in gear it needs to be smooth and it will idle down more than a jet when we load our pump.we can idle up if need be smokin remember that he cant with out grinding away!!!either way you go on cam choice call one of the techs at any cam place they can give you the best advice you are lookin for.prop boats cam different than jets do.imo keep the duration to a minimun and get as much lift as you can.that will help you create torgue.;) there are all sorts of opinions out there telling you what to do.im really fond of comp cams had excellent luck and power out of several different grinds they sell and had several ones speacil ground for me to my specs over the years.i like comp can you tell:)

[SmokinLowriderSS]

What year is your engine?
No fuel pump provision (mechanical) should make it a Generation 5 block.
A post '91 Gen 5 or 6 has a non-adjustable valve train.
Also, my cam can be backed off at idle to close to 700 RPM. Cut the duration to 270* and it would idle very sweetly, yet make much more power than the stocker you have. Although, to try to get my lift at that duration, would demand a roller cam.

[HTRDLNCN]

its probably a Gen5,and once I change the heads the valevtrain should be a non issue?
Whatever cam I get has to be able to idle well at 600-650rpm max.
Any higher and it clunks into gear which is bad for the Alpha drive
when its hooked to a big block.
What year is your engine?
No fuel pump provision (mechanical) should make it a Generation 5 block.
A post '91 Gen 5 or 6 has a non-adjustable valve train.
.

[cfm]

Well Mr Lincoln, it looks like 3wood over at SW already did the testing for you. :cool: 5-6mph in his boat (older 242 formula) is much more than I would have expected.
This is what's cool about the internet ! Running into someone who already tested what you are thinking of doing.
Speaking of thinking, I can pretty much say all of us above where giving you good /sound thinking. Problem is, in real life most of us have never tested this engine combo because with the $$$ and parts being used we'd all 100% be changing the camshaft also. Anyway, if 3wood is being 100% truthful (I have no indication why he wouldn't be - has nothing to prove and seems like a decent guy) then this may just be what you are looking for, if it's the direction you want to go.
What's the worst thing that can happen ? Needing a cam to put you where you want.
BTW: I believe the Gen VI Vortec head 454's (started to be used in '98?) where the first to receive OEM hyd roller cams.

[ck7684]

How much power can an Alpha handle??

[HTRDLNCN]

Thanks,I just went and read that ..
Sounds promising.
:D
Well Mr Lincoln, it looks like 3wood over at SW already did the testing for you. :cool: 5-6mph in his boat (older 242 formula) is much more than I would have expected.
What's the worst thing that can happen ? Needing a cam to put you where you want.BTW: I believe the Gen VI Vortec head 454's (started to be used in '98?) where the first to receive OEM hyd roller cams.