I like the 850 on the 454's. I prefer the dual-plane intake because it makes more low and midrange power than the single-plane intakes (longer runners). Dyno has dual-plane, Super V has single-plane. Otherwise they have about the same engines. Don't be fooled by the volumetric efficiency calculations. Marine engines can run over 100 percent VE. I'm going to bed. Call me tomorrow if you get a chance. 403-3962.

BGIII I ran both a single plane and a dual plane on my roller 502 and liked the dual better.....sold the single to JimV, he might still have it...it is an oval port my motor didnt turn over 5200 so the single plane did'nt help any and I lost some bottom end.
my.02