The Merc 525SC came with the Weiand 177. B&M's counterpart is the 174. Holley acquired B&M and Weiand. They still use the Weiand name but use the Holley name in place of the B&M designation.

I was thinking that the 525sc came with a weiand 256... Maybe i am mistaken.
Steve

According the the Mercruiser Shop Manuals (good reading! Buy them) the 525SC has an Weiand 177 blower running at around 5-5,5 psi on the 454 making 525hp.

The 2003 Mercruiser Racing HP575SCI has an Holley 256 blower running at around 5-5,5 psi on an 502 making 575hp at 5200rpm.

Ratchet - The 177 Blower should work very well in your application. You are correct Weiand did not offer a Marine 177 for SBC only 142. The difference from street to Marine would be crank spacing and Thermostat adapter.

Good Luck

a 142 Weiand or 144 holley would produce sufficiant boost for a small block with single carb app. I do
recommend an aftercooler and oil cooler if you plan to run the engine hard though. Blowers produce alot
of heat and stock coolers just don't do the trick. But
if you are looking for longevity out of this engine, I
would try to keep the peak cam range in the low to
mid 5000 rpm range and go with a bigger prop.
Blowers tend to help engines fly apart at high rpms.
As far as 383's go......some people swear by them...
others like myself believe they are not well balanced
engines and do not tolerate the constant higher rpms
of the marine world. Probably why mercruiser destroked
a 400 to make the 377 :) ...Anyway thats just an
opinion. If your 355's are set up right, it would not
be unheard of to reach 500hp with aftercooled "intercooled" blowers. Goodluck to you.

TO: 29scarab....yea they are noisey aren't they :)

what did u get for speed and what did you all do to the motor ?

Engine rpm has little to do with the actual blower rpm. You just need to size the pulleys correctly. Max blower rpm for a 177 is 13500 rpms. At 100% over driven you could spin the engine to 6500rpms. Stock 525sc was 100% over driven and made 5.5# boost on 454 ci. On a 350 the same ratio would make around 8# of boost.

I ran a street 177 blower for 13 years with zero issues on a marine 454. Great setup for stock or mild engines.