Converting a full race bracket motor to fast family cruiser

[Ren]

Lets say i wanted to pull the 598 out of my dragster and put it in a 25 daytona or similar style fast cat. What changes would you make? I'm assuming I'm going to need to reduce the compression down a bit and put a smaller cam in to take some pressure of the valve train, some water pump mods, and maybe go efi, but what else would you do to make it a "marine" engine for a fast cat? Trying to decide if i sell my rail no power and move this into a boat or just start over with something unknown.

598
Block Dart Big M Iron tall deck,
Dart Big Chief PRO1 18° 424cc heads,
Crower Crank 4.500" Stroke,
Crower Rods,
some mystery cam i cant find the paperwork for (over 1" lift) that will probably need to come out.
Ross Pistons 4.600, 12.5CC Dome 156MM Tall.
Approx 15.5:1 static compression.
Jessels Rockers for big cheif,
Edelbrock Big Victor Spread-Port Tall Deck Intake, currently running mechanical methanol injection, but also have a Holley 1250 CFM 4500 Dominator setup for it.
Moroso Vaccum Pump,
MSD Crank Trigger,
Balancer ATI Super Damper
Comp Cams Belt Drive.

Current setup makes about 1100hp n/a and goes 7.5s at 180 in my rail. There is a lot of good motor here. Only 50 passes since assembly. Just weighing my options. Let me know what you would do with it if you were me. Only rules are it has to be reasonably reliable (for a high horsepower boat). And run on some kind of fuel i can find reasonably close to Havasu, powell, parker...

 

[Eliminator21vdrive]

I would think that piston to wall clearance would need to be more with piston swap due to less block heat .

 

[Fastdadtsmith]

Hopefully @obnoxious001 will chime in. He builds quality motors.

 

[obnoxious001]

Lets say i wanted to pull the 598 out of my dragster and put it in a 25 daytona or similar style fast cat. What changes would you make? I'm assuming I'm going to need to reduce the compression down a bit and put a smaller cam in to take some pressure of the valve train, some water pump mods, and maybe go efi, but what else would you do to make it a "marine" engine for a fast cat? Trying to decide if i sell my rail no power and move this into a boat or just start over with something unknown.

598
Block Dart Big M Iron tall deck,
Dart Big Chief PRO1 18° 424cc heads,
Crower Crank 4.500" Stroke,
Crower Rods,
some mystery cam i cant find the paperwork for (over 1" lift) that will probably need to come out.
Ross Pistons 4.600, 12.5CC Dome 156MM Tall.
Approx 15.5:1 static compression.
Jessels Rockers for big cheif,
Edelbrock Big Victor Spread-Port Tall Deck Intake, currently running mechanical methanol injection, but also have a Holley 1250 CFM 4500 Dominator setup for it.
Moroso Vaccum Pump,
MSD Crank Trigger,
Balancer ATI Super Damper
Comp Cams Belt Drive.

Current setup makes about 1100hp n/a and goes 7.5s at 180 in my rail. There is a lot of good motor here. Only 50 passes since assembly. Just weighing my options. Let me know what you would do with it if you were me. Only rules are it has to be reasonably reliable (for a high horsepower boat). And run on some kind of fuel i can find reasonably close to Havasu, powell, parker...

View attachment 1259457

It would probably make sense to start over with something new. As you have already noted, many of the parts would need to be replaced to be pump gas compatible and to have reliability. On top of that, the outdrive style boat probably would never run the rpm that engine was designed for, so the heads would also not be ideal for the swap.

 

[Ren]

It would probably make sense to start over with something new. As you have already noted, many of the parts would need to be replaced to be pump gas compatible and to have reliability. On top of that, the outdrive style boat probably would never run the rpm that engine was designed for, so the heads would also not be ideal for the swap.

Thats kind of what im thinking. Yes spins to 7500 rpm quite happily. Its a bit too much bore for a blower application too, which is probably more the setup i want to end up with. Just a shame cause i know its a good one.

Would be a better fit in a small jet boat.

 

[obnoxious001]

Thats kind of what im thinking. Yes spins to 7500 rpm quite happily. Its a bit too much bore for a blower application too, which is probably more the setup i want to end up with. Just a shame cause i know its a good one.

Would be a better fit in a small jet boat.

With a cam and heads that large, it's really a drag race only application.

I have on my schedule a jet boat that a guy had an engine built for by a well known builder, but he handed him parts he bought from a drag racer. He didn't get the boat running for many years, and when he did this year he found he didn't like how it ran below 3500 rpm. I drove it here after seeing he was not comfortable driving it fast yet, and suggested a cam swap, and put the current one back in if he ever gets to the point of racing instead of a family boat.

 

[Teague_JR]

Agreed way too much cam, heads, and compression for boat use. Obviously it’s a bad ass NA race setup and could be turned down a notch or two in cam and compression and work in an NA marine race style application… but that still would be a long way from practical in a pleasure boat

 

[Ren]

Agreed way too much cam, heads, and compression for boat use. Obviously it’s a bad ass NA race setup and could be turned down a notch or two in cam and compression and work in an NA marine race style application… but that still would be a long way from practical in a pleasure boat

Thanks for the input, Ive talked to a couple motor guys now and its just not really the base i need for what i want to build. I think im going to recert the dragster chassis and go run it at vegas and bakersfield with a for sale sign on it to help fund a new float.