I pull a 9K fifth wheel with my 77 F250. It has a basic stock rebuilt 460. Bored 40 over with Sealed Power speed pro hypereutectic pistons, zero decked, balanced, oversized Manly S/S racing valves, smog bumps removed in the heads, exhaust ports cleaned enlarged and polished, Melling performance cam timed straight up with Mildon double roller chain, Crane lifters, valve springs & roller rockers, dual 2 ½” exhaust w/Flowmaster 70 series big block mufflers and MSD ignition.

The fuel system consists of a Carter P-4594 electric fuel pump with the mechanical pump removed, a Edelbrock 8190 fuel pressure regulator set to 5 psi. I put the Transadpt 2199 adaptor in place of the EGR and put the Edelbrock 8723 wood spacer between the adapter and the carburetor to keep the carburetor from getting hot and boiling the fuel.

The truck runs great and pulls like a diesel but the aftermarket carburetors don’t have the pull like that old Motorcraft did. I have tried both the Edelbrock 1406 & 1411 and am currently running the Holly 4160. It seems to run smoother with the Holley. The problem is with the aftermarket carburetors is when you open the back barrels. You can feel a surge in power but nothing like the old Motorcraft 4350. When you tromp down on that old Motorcraft it’s like going into passing gear. It will actually push you back into the seat but not so with either the Holley or Edelbrock. I am using the stock dual plane manifold and I am wondering if that is the problem. All the articles I have read say the low RPM engine performs best with the dual plane. I am looking at the Edelbrock 2166 dual plane performer manifold, does anyone have any experience with it? I have a Holly 17-6 open center adaptor and am wondering if that would help if I put it under the carburetor. I would like that Holley to give me the punch that the old Motorcraft did when those back barrels opened.

I am open for suggestions if anybody has any ideas.