454 help please and thankyou
 

Ok, I have twin 454-330 and would like to pick up 400 RPM. I have bought new exhaust, not installed yet, and I would like to change intakes and maybe if absolutely necessary cams and carbs. I would like to get better intakes and use my Q-jets, but if that is unrealistic I will buy new carbs. I don't really want to mess with the cams. Can anyone suggest any parts specifically with brand names and possibly part #. Thanks again for the help. DJW

An engine is nothing more than an air pump. The more air it can pump the more hp it can produce. Put your money into a good set of performance heads and good exhaust then next year do the cam , intake and carb you will be happy. Or have Jim V. rework your original heads and buy good exhaust.

the heads are a oval port really need change to the merlins .i had the 365 mag with 1.8 rockers,830 cfm holley,stelling headers,would turn 5400 rpm,no prop change

Depends on your budget and timeframe...

Quick and inexpensive: If you already have new exhaust, I'd say add Edlebrock Performer intakes. They will provide good torque on your engines. Use your Q'jets and see what happens.

I have an 1993 OMC King Cobra 454. I installed a Weiand Stealth intake manifold and replaced the stock corkscrew type mufflers with Shotgun Silencers and picked up 500 rpm. Now obviously my boat was really choked with the stock parts but its a good place to start.

330's have round port heads and just about every intake out there is an oval port. Edelbrock performer 2-o i think is an intake that will work with the 330 heads. it is ia q-jet base. put the exhaust on and a bigger spark arrestor and you might see a couple hundred rpms.

Hey DJW

I also have a boat with twin 330 - 454 engines. I located 2 factory GM high rise manifolds PN # 3883948 that I have cleaned out & blocked off the heat passage. These manifolds are cheap ! I am also porting my stock heads & replacing the cam. From all the research I've done I think the stock q - jet will work fine as I'm keeping the RPM's under 5000. My boat is a 28 footer that runs 66.7 on GPS now. How big is your boat & how fast is it now ?

Bo

Bo,

I have a 311 Formula with Bravos. It runs 62 on GPS. I don't want to get into the internals of the motors. I am looking for some worth while bolt ons. Weiand has a high rise duel plane intake for the peanut port heads that I am considering.


Cignificiant,

I have been looking at the Performer RPM but it is for oval port heads and I have the peanut ports. Will the Edelbrocks work? You don't think there is anything to be gained by changing carbs?

Thanks again guys, I don't mind spending alittle money but I don't want to waste it either. DJW

DJW are you sure you have the Penut Port heads? Have you actually removed the intake to look? I have yet to see a marine 330 with penut port heads on it unless it is a much newer one. What year are your motors? You can get the casting numbers and find out that way if you do not want to remove the intake. My bet is that unless you have a Gen 6 motor you have oval port heads. All my 330's have oval ports. Just a thought.

Jon

I'm not sure about whether the Edlebrock will work with your heads if they are the peanut-port. Maybe you could call their tech line?

I went to Edlebrock's web site, and if you don't intend to work on your heads I would stick with the Performer 2-0. The RPM has a higher RPM torque-band rating, but you'll only see benefits if you work your heads.

Jon,

I have one Gen 6 1999 and one remanufactured Mark 4 in 2001. I believe they both have peanut heads. Thanks for all the input, please add any of your thoughts. Good luck with the 302, I have a 311. DJW

You should have bought my 502's, now get back to work!!!!!!!

I think I'd install the exhaust system first. then something easy like the K&N spark arrestores, you said 400 rpm. This is boatin' time, not wrenchin' time.

They stoped producing the "Oval" port heads in 1984. Everything after that was the truck style "Peanut" ports. 230 vs 200 cc intake openings.

I like Mkast suggestion, get a good set of exhaust. That should give you about 200 rpm. A good flame arrestor like the K&N. I personally don't like the Rotten Chester but that's just me. I would go with a 750 Holley.

If you do have the Peanut port heads, they are going to be your limiting factor.

Bob

HIGHER RPM
 

THE COMBINATION YOU GOT IS REALLY NOT THAT GREAT -PERFORMANCE WISE BUT IM SURE ITS VERY RELIABLE.YOU WOULD PROBABLY BE BETTER OFF MAYBE JUST PUTTING THAT EXHAUST ON -HI FLOW ARRESTOR-AND A CARB SPACER THAT WOULD BE THE EASIEST AND MOST COST EFFECTIVE REMEDY.WHEN YOU GET READY TO SPEND SOME MONEY JUST REDO THE WHOLE THING BUT UNTIL THEN ENJOY YOUR SUMMER AND GET OUT ON THE WATER..:cool: