just entered 5th fleet North Arabian Sea in the last couple of days. i'm on the "IKE".

Im running a pair of 850CFM Holley Marine carbs on top of my 420 B&M blowers, on my 468s. Similiar to a 6-71.

Ive dynoed, and tuned this setup in the boat via a wideband. I am NOT running boost referenced power valves. Neither did mercury on their sc carb engines. I have 8.5PVs in the primaries, none in the secondary. My non boost cruise mode was in the mid 12's, and as RPM/Boost go up, it richens accordingly, and in the low 11's at wot.

I also wouldnt run the copper headgaskets. Two reasons. You dont need them, and second, they'll end up leaking.

Ezstriper, tell your son thank you, and 84F3LS, thank you also for serving our country. Be safe out there.

thanks !! guess blower vacuum at base is different, I had the issues on a 671 on a car and a 177 in a boat...also I agree with the copper head gasket thought, had a 565 Sonnys that ran in top sportsman a few years ago that used them...had to keep block sealer in it to keep from leaking...can't do that w/o closed cooling...