Looking at a boat with a pair of Merc "600hp" blown motors.. all the 600SC's that I've seen have 2 holleys, these only have a single holley. It's an early 90's boat, and the motors are not original to it, although they appear to be merc factory motors. Anyone ever seen 600hp blown mercs with single holleys? What's the story? I assume 502ci and flat tappet cams?

Blown single holley from merc would have been
a 525SC.

Thats a 454 based engine, flat tappet cam.

I second that sounds like a 525 sc motor 454

What they said. 468CI I think. around 7.5:1 comp. Virtually indestructable engines from what I have seen.

Probably a warmed over 525SC.

The Merc 600SC's use a 671 blower which only use dual carbs.

Thanks guys. It has a Merc 600 air filter on each motor.. I'll have to get more details, it must be a 525 w/ a smaller blower pulley or something, claiming 600hp.