round port or square
 

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?

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.

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.

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?

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.

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

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?

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

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.

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.

I like the OE heads but like said you have to put some time into them. This past winter I picked a bare set of 990’s for like 500 bucks on ebay. I lucked out. Besides them having some surface orange (it wasn’t even rust) they were fresh from a performance shop. Ported and polished super nice.
It was kind of a letdown in a way. I’ve been collection spring seat cutters, seal seat cutters and porting and polishing tools from the last couple head jobs I’ve had to do. I was ready to make them the nicest set of heads we ever owned. At least I got to use the stuff on some fine tuning of the heads and port and polishing the intake and exhaust.
My point is, if you are building a motor. You can use pretty much any heads you want (within reason).
I have a set of 049’s on a shelf. Come to find out they were 123cc when they were supposed to be 113 so you have to keep that in mind. The way to fix it is use the right pistons. Just like my 990 heads, I use .210 dome pistons which gives me about 10.25 to 1.
If it was me and I wanted to leave the door open for future upgrades I would look for a set of O/E square port, open chamber heads with 1.880 / 2.190 valves or bigger. Your valve springs will have to match your cam so you are building/rebuilding something anyway. Once you have your heads and know the chamber cc then you can get pistons that will get the compression number you are looking for.

I built a 489 a couple years ago and went with the AFR 265 ovals, as Haxby suggested. Went with partial CNC, upgraded to inconel exhaust valves, I think I was all in for around $2200 shipped. You could definitely finde these all day for less than $2500, unless prices have gone up. If you are worried about corrosion at all, AFR will hard anodize them for you to help protect against corrosion, but if you boat in salt or backish water, I would go closed cooling.

I ran a fairly mild hyd roller and a Dart single plane oval intake and the motor dyno'ed at 585 HP and 605 ft/lb torque. Torque band was very flat, it made upwards of 600 ft/lbs from a little over 3000 RPM all that way through 4500 RPM. These heads could EASILY support 600+ HP with a more aggressive cam. Keep in mind that the Dart intake and stock Holley 800 CFM carb that I used were probably limiting factors for power production.

You could probably run your oval port Air Gap with these heads and make a boatload of torque, but a single plane would probably work better if your cam is fairly aggressive. You could port match the intake to the "roval" shape of the intake ports on the heads fairly easily. I left out this step on mine, so there is some additional power that you could pick up. No matter what heads you buy, if you purchase them fully assembled, it would be prudent to take them to a good machine shop and have them checked out - pay particular attention to valve guide clearance, as they can be a little tight for a performance marine environment.

I have purchased the teague custom marine stage 1 cam hydrllic roller
intake lift duration centerline
cam lift .3450 226.0 107
valve lift .5865 226.0 107
exhaust
cam lift .3590 234.0 117
valve lift .6103 234.0 117

Also the boat is a fresh water only boat. Thanks for all the information guys it is very helpful

you got the crane 731 cam .

I would think that a cam with those specs would work very well with something like the AFR 265 or something similar.

Actually , the 731 crane is 226/236, @ .050..But whats interesting, is it looks like

their stage 1 is the 139011 crane
http://crane.carshopinc.com/product_...d/76045/139011

, stage 2 is the 139021 crane,
http://crane.carshopinc.com/product_.../153302/139661

stage 3 is the 139651,
http://crane.carshopinc.com/product_...d/16124/139651

and stage 4 is the 139661
http://crane.carshopinc.com/product_.../153302/139661



looks like Teagues camshafts come from this place. Possible they took the crane designs, and had someone else grind them for them.

http://www.andrewsproducts.com/autom...ing-capability

http://teaguecustommarine.com/em0011...nufacturer=867

The cam card says by. Andrews Products.