Merc set the 454 Mag Q-jet up with 0.068 primary jets, 0.041 primary rods (not 41B) and DA secondary rods.

Let me know if you need additional info.

CP Performance Marine has the 800 Marine Holley For Sale. Google CP Performance to find it. The specs between CP and Holley Marine seem to jive regarding acclerator pumps. I have seen 30 cc primary and 50 cc secondary and vice versa advertised in Summitt. The summit paper catalog also carries it. Mercury offers the carb with blue paint for $1200, Standard Holley Gold gives you a $700 discount.
I have blue one on 454 with blower. Great economy and awsome throttle response compared to running a 850 Holley.

Preuni if you go with the Quad . I have a fuel line that came off my 454 mag 365 hp if you need it?

I did the same swap because my 365 hp 454 with the carter would'nt start after only 20 minutes when hot. Starting fluid was needed after 2 days of sitting. I had to fab up some stainless throttle brackets and fuel line and also use a 1" spacer to clear the accelerator pump or it would hit the manifold. Did'nt notice any increase in top speed but think I gained some midrange and of course it starts if you just touch the key. Worth it to me!

Hey Rumrunner, what sizes does the Demon come in for marine??? Can we get them through you???;)