Performance curves BBC

[TollyWally]

I am trying to get my hands on some performance curves for a 7.4 (454) marinized by Volvo. Specifically Engine # BB740 A SW 410012601586817
8:1 compression. Thanks for any clues

[jsh]

I will email to you performance curves for a crusader 454. Should be close enough. let me know
john

[TollyWally]

John,
That would be absolutely wonderful, I greatly appreciate that.

Thanks

[No Joe]

I'd like a set too.
Mine are 350hp (on the valve cover) w/ Q-jet, but I keep hearing 320hp. Whats the difference?
I know on the 318 Chrysler the difference between 195 & the 225 hp was a 4 barrel carb.
Fred

[TollyWally]

Hey Joe,
I have that data on another hard drive that is currently not hooked up. This is a super place to get motor info. They are drag boat guys and some of them are extremely knowledgable.

http://www.performanceboats.com/html/forums/

Generally speaking many of these 454 motors are quite similar in real horsepower despite advertising claims. The drag boat guys concencus is a 320 hp motor might make 280 on a good day. Look at your compression ratio for clues.

I will try to get those curves for you but it will take a while. Meantime why not put all the specs of your motor up.

[jsh]

hey joe I posted the curves on the other thread you posted on recently (prop size) in the inboard section
its on page 1 as a .pdf attachment
john

[powerabout]

I watched a Mercruiser 330 ( 454 ci) on a dyno in Australia years ago.
It made 260+ horsepower and 330 ftlbs ....mercury dispute this.
A 370 ( high performance 454) made 300+ and 370ftlb
A 260 ( 350cu) made 220+ and 260ftlb
(These were all with dry headers not the marine manifolds/risers from the engines)

I also know a 260 and the old 225hp outboard pumped the same pressure on land & sea dyno...

As mentioned above the v8's have very low compression so are not as potent as you think

[jsh]

this type of comment does nothing to further anyone's knowledge. if you have run a 7.4l on a dyno post the results. it is unacceptable to claim a contrary posistion without providing data that is at least as precise as the data you are challenging.
I'm just saying accuracy is important that's all
john

[powerabout]

I thought I was agreeing with Tolly?
It was 20 years ago so sorry I dont have the sheets
Where was the precise data I am challenging?
I would guess Land & Sea might still have the data for production engines.
But I think they just listed max dyno pressure if my memory serves me?

[jsh]

here are performance numbers published by manufacturer. I posted some time ago to further a different discussion.
john