8-71 or 6-71?

[PF468Blown]

Hey guys, here is what I got. I have a 525SC (I thought it was), it has a B&M 250 blower in it. The blower was powder coated black. It came out of twin screw boat (original engines). I thought it was a factory mercruiser engine, it came with a single dominator carb. Does mercruiser make a package with this combination?
The motor was totally rebuilt by Paul Phaff racing. I bought the motor complete oilpan to carburator, never been run. The rebuild was over 3 grand.
Here is what I want to do. I would like to put a larger blower on it. Is the 8-71 the way to go, or should I run a 6-71? Are these motors strong enough to run high boost, or should I get something else?
I would like to take the B&M 250 and put it on another BBC that I have laying around and have 2 blower motors to use. Any help/info/comments would be great.
[ February 05, 2003, 09:39 AM: Message edited by: PF468Blown ]

[Craig]

If it's a true 525 SC, the blower is a 177 Weiand, not a B&M 250.

[Liberator TJ1984]

8/71 would be better , spin it slower and still make good power and boost...

[PF468Blown]

I guess I need to do some research on what I got.
I thought it was a factory engine package. Since it is a B&M 250 blower/single carb, what should I expect for horsepower with this combo?
I guess the bottom line is, will this motor be strong enough to put a 8-71 on with 7-10 pounds of boost?
[ February 05, 2003, 09:43 AM: Message edited by: PF468Blown ]

[PF468Blown]

Who should I call to get some answers to all of these questions?
[ February 05, 2003, 10:44 AM: Message edited by: PF468Blown ]

[DUCKY]

The factory 525sc was basically a 454 mag under the blower. I wouldn't put a 6 or 8-71 on top of one without pulling it, and dropping the pan for parts inspection. I doubt yours is a factory unit though. The 525 SC had a 177ci Weiand blower and a 850 Holley, not a Dominator, and I think they were powdercoated blue. Or if you have the info, contact the engine builder and find out whats in the bottom end. If you have a choice, go withthe 8-71 and turn it slower.

[PF468Blown]

I there #'s on the block the help me figure out what I got?

[DUCKY]

If it was a Mercruiser system, there will be a small tag on it somewhere with a serial number. I think they are usually on the bell housing flange above the starter boss. It's only about 1" x 1.5" and it's aluminum and riveted to the block.

[paradigm shift]

Go with the 871 if it was me. If it was rebuilt by phaff they will have all the specs on the motor and could help with set up.

[PF468Blown]

I got all the specs, for it 3 pages worth. Thanks for the info.