Hammered

Ok, Time to tear into lightly modified 330hp 454's. So as long as I'm building might as well upgrade.

2 years ago we replaced the stock Intake, Carb & Ignition. I went with a Edelbrock Aluminum Dual Plane RPM Air Gap Intake, topped with 750 Demon Carbs which I then had reworked by Gary Williams and then added MSD Spark, Coil & Distributor.

Due to a noise in the top of the port motor I'm pulling them and going to rebuild. First of all the old peanut port heads have to go. my question is do I go with Aluminum or just a better flowing set of Cast? Is the price difference between the two worth it for the weight savings. I also want to switch to roller rockers but do I switch to rollor cam too?

I wasn't planning on tearing down the Short block but what are your thoughts on that. Should I and what should be done to it if I do?

I'm hoping to get somewhere around 450hp when we go back in without breaking the bank. In other words I dont want to spend 4k per motor on rebuild or I might as well buy a new Long Block.

What do you think? where do I go from here.

MILD THUNDER

iTrader: (3)

Those engines have dished pistons. A typical open chamber convential head your gonna be 8:0:1 or less. That kinda hurts.

I see your on a tight budget. An option is to get some vortec 454 heads from a 96-00 chevy/gmc truck. Have them freshened and cleaned up. Bolting these on will put you around 9:1. They will be a improvement over the peanuts.

Budman II

iTrader: (1)

How many hours were on the engines before the noise started? Was it valvetrain noise or something else? Are they Merc engines or something that someone dropped in there? If Merc, mag 454 or 7.4L? All of this plays into how much money you will need to spend to hit your goals.

AFR 265's can be had for around $2200, complete with inconel valve upgrade, but then you will probably want to upgrade to a more aggressive hyd roller cam and better exhaust to take advantage of them, and you will probably surpass your 4K limit in a hurry. Are your Air Gaps oval port or rectangle port? If oval, you can use them for the AFR's, or you can take MT's advice and get some better large oval heads. Keep in mind that the Vortec heads will probably require some machine work, better springs and retainers, and possibly an upgrade to larger valves to make them work well.

Hammered

My budget is about 10k. Less is always better but I think I can get two decent running motors for that. Just can't decide weather to build on the stock base and spend more on top end like aluminum heads, roller rockers & roller cam or build the bottom end and do less up top. I know Summit has 454 long blocks rated at 415hp for under 4k. But even that still needs upgrading.

Hammered

They are merc 7.4l not mags. They have about 550hours on them. And the noise was definitely in the top end. The intakes are large oval port.

MILD THUNDER

iTrader: (3)

That's a tough call. I see you have a Scarab III. Those things are tanks. My buddy has one. Takes a lot of power to get them moving.

He's got 454 370HP engines that been turned up. They have more aggressive cams, single plane intakes, GM rect port heads, stellings headers. Boat runs around 65ish. Engines probably make 450-475HP or so.

I guess a lot depends on how fast you want to go, and if you wanna burn up that 10g or more. Chances are if you sell the boat, your not gonna recoup the money invested. What exhaust do you have? Stock cast iron? I think this is what I'd do, to gain a little power, keep costs to a minimal, and get you boating again. Assuming the oil pressure and blowby was minimal. 550 hours really isn't that bad for a 330 engine, but you did change carbs, so if they were overly rich or overly lean, that could have caused ring seal issues. But its not unheard of for those engines to go 1000 hours.

Replace the stock peanut port heads with Vortec heads. Compression gain alone will probably net 25-30HP, plus they flow a little better than the peanuts. You'll need the correct valvesprings installed and new rocker studs. Roller rockers would be nice addition.

Stick with a flat tappet cam, just a bit more aggressive, something like the Speed Pro CS1139R, which you can pick up for around 100 bucks.

Crower Cam saver lifters=100 bucks

New timing chains

New Gaskets

Find some 496 aluminum mercruiser exhaust manifolds. These are usually available for cheap, and flow better than the cast iron stuff, and weigh less.

Budman II

iTrader: (1)

Hammered, let me know if you decide to go in the direction of the vortec ovals. I know a guy near me who has many sets of these from core engines. Could probably get them very cheap. Shipping would probably run about $80 per set, depending on where you are.

endeavour32

iTrader: (4)

Follow Mild Thunders advise, it will be the most bang for your buck. If you go the aluminum head route you're going to have close to 10 grand an engine to take advantage of the heads. Which would really mean starting from scratch as you can't push a 330 really hard as its a 2 bolt block, cast crank, wimpy rods and cast pistons.