98scarab

I have a 97 scarab 22 with a 454 and a carb. The engine busted a piston and i am in the process of redoing the engine. The bottom end consist of forged stroker crank, srp 30 over pistons, scat i-beam 6.385 rods, and a teague custom marine cam. I already have a rpm air gap oval port intake. The question is should i stay with an oval port head like the edelbrock rpm heads or go to a square port head. I would like to stay under 3 grand for a set of heads. What would a good exhaust to run on the boat also?

MILD THUNDER

iTrader: (3)

So, you have a 489ci engine?

I would skip the edelbrock heads all together. You'd be much better off with a set of good performance heads, from AFR, Brodix, Dart, etc.

The question you have to ask yourself, is, how much power are you wanting to make? There's thousands of 454 "Stroker" combo's out there running around. 600HP is doable with the right cam/heads/induction, on 89 octane.

endeavour32

iTrader: (4)

Check out the AFR 290 oval port. It's right in your budget and you will be hard pressed to find anything that will flow more than it for the price, or size of runner. Also don't forget when comparing heads to compare the mid-lift numbers. These are equally important. I agree with Mild Thunder- say away from the Edelbrock heads.

98scarab

Yes it is a 489. I would say i would be satisfy with anything from 450-600 hp. My main thing would just be a good dependable motor that i wouldn't be scare of to run hard every now and then. On the heads the afr 290s yall suggested look like a very good head that i am leaning towards. With the exhaust port being raised would i run into a problem with exhaust and could i run something like a eddie marine thunder exhaust or would i need something more like a lightening headers?

endeavour32

iTrader: (4)

I've run the AFR raised port with stock exhaust transom holes without any issues. The problem comes when you run pipes that extend through the transom. Then the wiggle room is minimal. The real determining factor on what exhaust, is what cam are you going to install? If you are going to buy new, I would go with Stainless Marine.

ezstriper

the performer RPM ovals(but they are not std ovals) are good for 700hp but you need a intake that matches

dereknkathy

your 450 to 600 hp goal can be attained with just about any head. I am not suggesting them, but peanuts can go to 500 hp. the OEM rectangles you already have can do 500 easy. as could 049-781 oval with a little work. now, if determined to spend the money on aluminum heads, that is another issue. where do you boat? salt, fresh or brackish water? heat exchanger, or open cooling?

MILD THUNDER

iTrader: (3)

Problem with oem heads that people fail to mention, is the amount of work they need to make those numbers. Reconditioning an old set of heads, spending money to clean the castings up to get them flowing, and so on, costs alot.

These guys on the internet will make you think you can go to the junkyard and pick up a set of heads off a 1985 chevy van, and bolt them on and make 500 plus hp for 30 bucks.

Those gm heads have std location ports, poor combustion chamber design, guides going thru water jackets, and alot of other downsides. Sometimes, youre money, reliability, and horsepower ahead to go with a quality set of aftermarkrt heads

HaxbySpeed

I don't know if the port has been improved on the V2 290's but the V1 wasn't that great, the 265's with a bit of clean up were a better value. Unless you need the smaller chamber for compression, I'd get the 305's and use the money you saved vs the 290's and buy a new intake. As others have said though, there are a lot of options that will get you to the power level you're looking for.

Baja Rooster

iTrader: (1)

I have Edelbrock rpm performers and my machinist put a lot of work into them getting them dialed. Now they're a solid set, but he had to quit selling them because their quality control has been the pits. I like them because they are nice and torquey down low, but need some tender love first and are limiter for max HP.