Jon (Carbking) has made a very good suggestion with the 2G series Rochester. It's one of the best designed, most reliable carburetors ever built. You'll need to go with an intake designed for a Mercruiser inline six, I believe it's the "165" series since Mercruiser rates their engines by horsepower rather than cubic inches, or use an adapter with the Offy 4 barrel manifold. Just DO NOT try to funnel the mixture from the 2G down into the stock 1-barrel manifold. Creating that kind of choke point cancels out any possible power gain- - - -you'd be better off with the Carter 1 barrel Jon G recommended.
Jerry
