A few Questions
 

So im going to rebuild (upgrade) my 454 / 330hp and am looking to get around 400+. Id like to spin it around 5200. My boat is a heavy (5850) and I run a bravo 3 (2.0:1) and 28p props. Im shooting for 60 mph (runs 44 now with 26p and 4400 max rpm). Ill be installing 454-502 Mag heads, 454-502 Mag intake & EMI exhaust.

Whats the max compression ratio Id want to stay at to run pump gas ? 91 ROM

Will the stock crank handle the compression and RPM's ?

Will the stock rods handle the compression and RPM's ?

Will OEM pistons allow me the compression I need to reach my power goals. (thinking +.030")

Piston Pin type. pro/cons over pressed or full floating.

What type of cam/followers ? Hydraulic or flat (pros and cons)

What cam specs should I stay near to achieve my goal (min / max lift, duration, overlap, etc.). I want something with a fairly smooth idle and a wide power band (i pull kids on tubes most of the summer and do some slower cruising).

What benefit is there to running a smaller cam, but a larger rocker ratio ?

What effect will roller cam, rockers and lifters have on power output ? (how much is a typical gain....bang for the buck)

Double row chain vs. belt timing drive vs. gear drive ?? pros / cons

Im trying to figure where the best $$$ spent is going to yield the highest results and still maintain longevity. If you know of a basic build parameters that have worked for you and would share them, please do. Im not against a stroker crank either, but would need to know rod length and any special piston configurations. Im not going to assemble/tune this myself, but the better informed I am at deciding which way I would want to go, the better off Ill be when deciding.

Thanks in advance for taking the time of read and reply here.

Going to need quite a bit more than 400+ hp to move that boat like your wanting to do. It'll get expensive real quick for what you'll need starting off with a 330.

I think you might need more like an extra 200HP.

Would a blower be the cheapest route?

fixx
 

your best bang for a buck would be a 496 stroker kit..it will be the best money you ever spend..for about a 1200.00 you can get crank rods and pistons rings bearings..you will just have to prep the block and clearance it for the extra 1/4'' arm but will be well worth it..spend a extra 500.00 and get a forged crank..also pic the 6.385 rods..you will need to have the flywheel zero ballanced and have the counter weight milled off if you decide to go forged.if you have a 2000 block then you will already have a roller cam..as long as you dont go over .575 lift you can save some money and use the stock roller lifters with the cam upgrade..

I could come up with a 502 block to start with if that would be easier to achieve my goal.

fixx
 

first,,am i reading it rite? z302? 30' single engine boat?

9 to 9.5:1 with iron heads. Maybe more with aluminum heads. I'd target 9.0 for starters.

This is a moot point since 400+ HP will not get you to 60 mph. As stated by others, you need at least 600 hp with that boat.

With the Bravo 3 you are limited by prop selection and 5200 rpm and 60 mph is about the max you will see with the 28" props. I'm not sure the Bravo 3 can handle the HP required to get your boat to 60 mph.

Yes. Others with 502 MAGs have seen 52-55

Nick

It's a target.