OMC crossflow V6 - Higher compression = better fuel economy?

[kielbasa]

Hi guys, have a 1990 GT150 on my family runabout.
I've usually heard that increased compression helps with low and midrange punch, sooooo my question is if I would slap on a set of higher compression heads, would it help with my fuel economy? I usually use the boat for skiing and putt putty driving, which means it's usually operated anywhere in the 2500~3500 rpm range. And since I run E0 (91 octane) fuel anyways, would it be a worthy experiment?
Or would I have jet the carbs so much richer which would negate any increase in efficiency? Your thoughts? Thanks for any input!

[FORBESAUTO]

Definantly won't hurt and a very good chance it will improve. Anything to make it more efficient will help fuel mileage. The more power it makes, the less it's working. I know my modded mercs are much more fuel efficient at cruising speeds than my stock 200 was, even with the much larger jets. Takes less throttle to accomplish the same speeds so uses less fuel. Jmo

[BarryStrawn]

A GT 150 had better cylinder heads than the base 150 models. So maybe check what heads are on it now. Do you know what the cranking compression is?

If you went to the early heads from 1978-79 it will need 93 octane. At least that is my experience with the large bore engines.

Casting numbers on the GT heads should be 0332545 and 0332544 .

[kielbasa]

Correct, I do have the 544/545 heads.....unfortunately the only 93 octane we have around here is E10.
I have not checked cranking compression, my assumption is 90~100, but that's all it is, an assumption.
I am led to believe the standard GT heads are 87 octane friendly, maybe I would be better off just slightly milling my existing heads?