How much power?

[Geronimo36]

Depends on your definition of reliable. Smitty aka Arcticfriends found that leakdown after 150 hrs was pretty poor at that boost level. Set up and tune has to be correct also. We're lucky that we have all of that water to use for cooling. Just use a restricter instead of a thermostat and jet rich enough to keep the piston tops and oil from overheating.

I hear ya, it's all good. My definition of reliable is 250 hrs on rebuild for a blower motor and 500 hrs NA'ed (valves/springs @ 250 hrs). I guess it also depends what blower you're running whether it be roots, centrifical or whipple etc. The roots make a lot of heat and will shorten lifespan and be more prone to detonation. I hear the new whipple is making some serious HP on the 525hp.

[AGITATOR]

any dyno sheet should show that at 5650 rpm the hp and torque cross on the sheet if they dont they dyno's info are bogus and the fuel is at 100 oct with torco leaded booster at that mix

[HaxbySpeed]

any dyno sheet should show that at 5650 rpm the hp and torque cross on the sheet if they dont they dyno's info are bogus and the fuel is at 100 oct with torco leaded booster at that mix

You're about 400rpm off there chief.. And it's a mathematical equation that I'm pretty sure isn't affected by octane...

[HaxbySpeed]

(Torque x Engine speed) / 5,252 = Horsepower

[Mrhorsepower1]

A member here, Ben Perfected is making 800 hp with a 502 naturally asperated single carb. I think he built them to the old B class rules. It does take a few more rpm though.

I had built about 5 race boats back in the "A" and "B" class days also. 510 cu.in , 9.5:1 compression, iron heads, single carb. wetsump oiling, 15.5 inch primary header tube length, and we made 810 horsepower @ 7000 rpm. The engine would run 7000 rpm all year long and never come out of the boat till after 14 races before freshen!

[PatriYacht]

Very impressive.

[Trim'd Up]

I had built about 5 race boats back in the "A" and "B" class days also. 510 cu.in , 9.5:1 compression, iron heads, single carb. wetsump oiling, 15.5 inch primary header tube length, and we made 810 horsepower @ 7000 rpm. The engine would run 7000 rpm all year long and never come out of the boat till after 14 races before freshen!

So I should be able to easily make 800 with the 555 that you talked me into right? I will be getting with you after the holidays to spend some money.

[Geronimo36]

I had built about 5 race boats back in the "A" and "B" class days also. 510 cu.in , 9.5:1 compression, iron heads, single carb. wetsump oiling, 15.5 inch primary header tube length, and we made 810 horsepower @ 7000 rpm. The engine would run 7000 rpm all year long and never come out of the boat till after 14 races before freshen!

Very cool!!!

I bet these 598's can make much more than the 800hp they currently do!!! http://www.seriousoffshore.com/forum...p?t=327&page=2

[Mrhorsepower1]

Some of the boats I am referencing to are the ex powerboat mag Larry Smith Scarab " Let It Roll", "Feel The Rush", "Traffic Light", and "Rum Runners" to name a few. I loved the classes!!

[stinger]

I had built about 5 race boats back in the "A" and "B" class days also. 510 cu.in , 9.5:1 compression, iron heads, single carb. wetsump oiling, 15.5 inch primary header tube length, and we made 810 horsepower @ 7000 rpm. The engine would run 7000 rpm all year long and never come out of the boat till after 14 races before freshen!

So what combo does this? most marine engines are lucky to get 1.1 hp per cube.Our was this more a drag motor type combo?

[AGITATOR]

i no oct does not have anything to do with it i was answering his other question but you are right on the curve i stand corrected

[AIR TIME]

DEANS been putting together a 572 intercooled 1071 hope to see 1050hp and in the fall take my 670hp motor 509 and make it more like 750hp with his custom= cam/intake/ and I have the carb from him.its my p5 motor hope to get back into some racing after my knee heals and insurance says I can play. so this summer I want to break a 100 or the other leg trying. those A class motors ran nice in those boats wish I meet you back in 95 when I started messing with my 502 merc.Dean helped the guy with a twin motor to mine that had troubles with his cam and other stuff and it ran good last fall so mike should put some hours on his 572 this summer .I just wished last year that he sent it to you Dean to inspect.Can wait for mine getting the bug.haa hah.

[MOBILEMERCMAN]

Some of the boats I am referencing to are the ex powerboat mag Larry Smith Scarab " Let It Roll", "Feel The Rush", "Traffic Light", and "Rum Runners" to name a few. I loved the classes!!

The good old days. As I remember A allowed 510" and B 460"