I have a 24 foot predator Marine viper I am in the process of redoing top to bottom. Put bravo two upper with Brovo 1 lower. Should handle what I throw at her.

I have a 454 330 I want to rebuild and add a few horse to from what I hear the crank is week and cant go over 400 425 hp want to know if its true and what have guys had good luck doing with these motors.

I would like to keep the budget down so I'm not going to buy a forged crank so I asumming heads cam intake And carb and exhaust.

Pulled motor and tore down bottoms end look clean and not much wear no scaring at all but my question is the pistons have a 6 on them I'm curiouse if that means .060 over or not

I am having it cleaned and block tested to make sure it's good and I'm planing on putting all new bearings and stuff in the bottem end.

Heads on it have lots of wear and look like hell so I need new ones.

I have an edlebrock 750 on it right now want to reuse it it also has msd on it but I have no problem changing that out to.

Just looking for what people think would be a good set up for it

Boat only weighs 5000 and won't go over 47 right now would love to hit 60 or more if possible I have a bravo 2 up brovo1 lower 23 pitch 3 blade 1.5 ratio on it

I was also thinking about going to a LS motor to

Also has drive exstension on it with duel hydrolic steering.

You can prob find a good used forged crank for a reasonable price. Wouldn't spend or do much with a 330 bottom end. Small rod bolts, cheap casting rods, cast pistons, great motors when stock and last a long time if maintained, just not performance oriented

Well it's not out of the pic I might buy a forged crank and rods and pistions but I'm getting up into 5000 for everything and I don't know it's that motor is worth doing all that to

do some shopping around. I wheeled and dealed and traded for a 454 for my V-drive that is four bolt, forged, cross drilled nitrited crank, forged rods and pistons and square port heads. all in all I had about $300 in the deal. I took that and freshened it all up as the crank and rods looked like new. deals are out there so there is no sense in spending money on cast stuff when it does not cost any more to rebuild a forged motor.

Problem is that my motor had some water in it and I think it's cuz of my heads being bad and wore out

A couple flavors,

*1986, MIE/340 (7.4) 454 Big Block
Dip it and hone the decks and cylinders (the cylinders did not need to be cut and are standard bore)
Block was detailed with all casting debris removed
Stock seasoned crank (also cleaned up)
Reconditioned connecting rods
ARP Rod bolts
.210 Domed Speed pro pistons and pins. (They should give me 9.38 to 1)
Molly piston rings
Federal Mogal bearings (cam, main & rod)
Cloyes true double roller timing chain
Moroso Chevrolet 454 Stud Girdles #6729 BBC
Crane #132561 hydraulic cam--Duration Advertised: 298° Intake / 306° Exhaust Duration @ .050'' Lift: 228° Intake / 236° Exhaust Valve Lift w/1.7 Rockers: .530'' Intake / .551'' Exhaust Lobe Separation Angle: 114°
Crane #99277 lifters
Comp Cams High-Tech pushrods #7954
Completely refreshed Chevy 14096188 heads / 454 Open / 118cc / 3angle valve
Comp Performance Valve Springs #911-16
Pioneer head bolt sets
ARP 1.90 rocker studs
Norris S/S 1.7 roller rockers
Melling H/V oil pump
Melling HV oil pump shaft
EDELBROCK BBC R2 AIRGAP INTAKE
JEGS 15951 - Mechanical Fuel Pump
Pro Comp Ignition
Pro Comp distributor
Super Stock coil
8mm Accel Hi performance wires
New single wire alternator
Mini (gear reduction and fully marine) starter
Edelbrock 800 carburetor
12" aluminum, oval air cleaner (with K&N filter)
Brass freeze plugs
Stainless steel bolt set
4” Stainless steel risers
GLM aluminum exhaust manifolds
Sherwood motor mounted raw water pump.

1987, MIE/340 (7.4) 454 4 bolt main Big Block
Dip it and hone the decks and cylinders cut .060 over
Block was detailed with all casting debris removed
Scat 9000 Crank 4.25, 496 stroker
Scat 26385P - 6.385 in. Connecting Rods - Bushed -I Beam Forged 4340 steel
Howards Cams 120255 - Max Torque Retrofit Hydraulic Roller Camshafts, Hydraulic Roller Tappet, Advertised Duration 288/294, Lift .585/.610, 112 L/S
Howards Matching Valve Springs 98636 - 130# / 330#
Cloyes Gear 9-203 - Cloyes Wear Plate, 031 in. Thick,
Maxspeeding Hydraulic Retrofit Roller Lifters
Probe 496 Dome Top +18.0cc - SRS Piston Set
Clevite 77 Cam Bearings
Federal-Mogal 4400 M20 Main Bearings
King Engine Rod Bearings CR849HP
Cloyes true double roller timing chain
Mahle - Plasma Moly Coated piston rings
Melling 10778C (Anti-Cavitation) oil pump
Melling HV oil pump shaft.
New Harmonic Balancer
Rotating Assembly Fully Balanced
Comp Cams High-Tech pushrods #7954
Completely refreshed Chevy Heads 14096188 / 454 Open / 118cc / 3angle valve
APR head bolt sets
ARP 1.90 rocker studs
Norris S/S 1.7 roller rockers
Seal Power Gasket set
EDELBROCK BBC R2 AIRGAP INTAKE
Pro Comp 2752 Fuel Pump
Pro Comp Ignition
Pro Comp distributor
Super Stock coil
8mm Accel Hi performance wires
New single wire alternator
Mini (gear reduction and fully marine) starter
Edelbrock 800 carburetor
12" aluminum, oval air cleaner (with K&N filter)
Brass freeze plugs
Stainless steel bolt set
4” Stainless steel risers
496 MerCruiser exhaust manifolds with Tall Risers
Sherwood motor mounted raw water pump

Rare boat, Where are u located?

Not only do you have the cast crank, weaker rods, but the pistons are probably dished also .

If the block gets a clean bill of health, be sure to have it sonic tested if its a 30 year old marine block. You can find GM Steel Cranks for around 200 bucks. Ideally it would not be ground, and just need a polish.

Theres lots of options for new rods, and not worth messing with the ones you have.

Speed Pro Makes a nice small dome piston, basically what the mag engines had. Usually end up around 9:1.

Basically what you'll have there is a Magnum shortblock. used on the 365,370, 400, 420HP flavors of the 454. Plenty strong.

Obviously going with new heads, like some Dart, edelbrock etc, is a wise choice. However not always in the budget. IMO, dont waste your time with GM oval port heads. If used heads are what your budget allows, try to find a set of fresh GM Marine Rect port heads, off a Merc engine. Lots of time you can find a nice set right here on oso for cheap money.

No need to reinvent the wheel here. Just copy the Merc recipe's for the 420HP 454. You can go to a next size hotter cam than the 420's had. I have the part # for the crane flat tappet we used in my buddys 454's. Its like 236/245 @ .050 114LSA. Did not revert water with stock exhaust.

If your going that route, I have
Stock 420 Intake manifold (GM Alum dual plane. Some had Weiand single plane, but I have the GM ones)
Stock 420 Quadrajet.
Crane Gold Roller rockers (came stock in the 420's)
New set of lifters
1 Set of Reconditioned GM Dimple Rods with ARP bolts

I can set you up with a nice package deal on that stuff.