Warmed 454 Intake Mainifold Choices?
 

Before someone writes "Do a search" Please check out these spec's.

My re-worked 454cu in/420hp motors were finished as follows:

Dart HP500 Intakes.... :(
990 GM heads
Comp Roller Rockers w/ stud girdles
Comp Roller Cams
Gross Lift - .589 intake/.612 exhaust
Duration - .236 intake/.242 exhaust at 114* lobe seperation
Bored .030 Over/SP Forged pistons at 9:3 to 1
Holley 4150 jetted at 79/90 w/6.5 power valves
Balance Crank assembly, etc

The motors made 529hp at 5750 rpm and peak torque was 505.6 at 4750rpm's. The lines cross at 5325 rpm's.

The problem is that my boat is a "lead sled" 7050lb dry " non-stepped 89' Formula 272" and I can't spin my props (hydromotive 23's) over 5000rpms.

I don't think this intake is helping. I need to bring the peak HP down in the "usable" range of 5200-5300 without re-pulling the motors for a Cam and intake swap. I do however want to choose a intake that can be used when I do re-grind a cam with about .230/235 duration and 112* lobe seperation.

Edelbrock RPM Air Gap?
Weiand Stealth, X-CELerator? Team G?
Victor Jr.?

Re: Warmed 454 Intake Mainifold Choices?
 

I'm leaning towards the Edelbrock RPM Air Gap.

Anyone have some numbers using one on a 454?

Re: Warmed 454 Intake Mainifold Choices?
 

I'm using the HP500 Dart Intake now and can't seem to pull any RPM's. I don't want to lower the pitch on the props any further.

I am going to check the timing tomorrow on both motors. I was told to double check timing since the shop DYNO MSD boxes were used and then I set my motors up w/ new MSD's out of the box.I can't see how the Dyno MSD box timing could be different but you never know.

Are you refering to another Dart single plane?

Re: Warmed 454 Intake Mainifold Choices?
 

Total at 38*. I asked my builder if it was too high. He says NO!
He said these Intakes dyno'd best at 38* on these motors.

Re: Warmed 454 Intake Mainifold Choices?
 

Wieand xcelerators were recomended to me. Especialy if your heads are stock.

Also you might want to try a Bravo1 prop instead of the Hydromotive. I understand they have a tendancy to lift the transome,which will make you go fast, unless you don't have enough leverage to carry the bow, then you'll go slower.

Re: Warmed 454 Intake Mainifold Choices?
 

mtgbiker,

With that kind of horsepower you should have no problem turning those props close to 6000 rpm let alone getting over 5000. I have an 89 272SR1 and when it had stock 454 Mags 350hp I was able to turn 25p Hydromotives 5100 at 72mph. The only mods I had at the time was Stainless Marine manifolds and Imco Shorties. Without the Shorties or the Stainless manifolds (saw no increase with the manifolds) I was able to turn 23p Mirage props 5200 at 67mph.

I would suggest you check timing and make sure you are getting enough air both into the engine compartment and that the flame arrestor can flow adequately.

Re: Warmed 454 Intake Mainifold Choices?
 

I run a comperable set up, 540 lift, 236 duration hydrolic roller cam, dart cast heads, elderbrock air gap intake, 750 elderbrock intake, lightening headers...

I make max HP at 5400, 440 hp, two motors with identical setup, within 2 HP of each other.

I would look at the dual plane air gap, it may lower your max power RPM's slightly, but not alot.

As said earlier, look at using props to change RPM's.

Re: Warmed 454 Intake Mainifold Choices?
 

what outdrives and gear ratios are on that boat and what is your speed??? that cam sounds big for what you are turning that engine at, sounds like the bottom of the page cam!! that would probably explain your low torque numbers

Re: Warmed 454 Intake Mainifold Choices?
 

Like you said, you have a heavy boat. It appears your camshaft selection was a little on the agressive side. For a heavy boat, you want torque, and you really don't have great torque numbers. Maybe check with someone like RMBuilder and let him select you a cam that is more suitable for your heavy boat and will complement your other engine components.

Re: Warmed 454 Intake Mainifold Choices?
 

Is the Dart intake available in an oval port? Use that with the rect heads or change the cam as you suggested.