Truck they are going into is a 85' F150 reg cab long box 2wd 3.55's

I have both an 85 and 96 300's efi is removed. They will receive a Offy DP and 390 holly and the efi manifolds from a 95, and Davis one wire HEI ignition.

From what i have seen there pretty much identical aside from the combustion chamber design, and the 96 having the knock sensor and no fuel pump boss milled out.

Both Engines have 180-190k Kilometers,

will be bolted to a Mazda 5psd.

What engine will give the better torque and power or will they be the same? I may add a set of Cloyes gears depends on suspension parts needed

Thanks all
Joe

 

The internals will be completely identical. Same bore, stroke, cam, etc.

If it were me, I'd go with the '85 since it would allow you to leave the head on as well as use the stock fuel pump. If you use the '96, you'll have to get an aftermarket electric fuel pump, and swap heads around. If you have the heads off, you have the extra costs of getting them checked over for cracks (something you want to do whenever you remove a head, especially at that mileage), resurfaced, and new head bolts and head gasket. That adds up.

 

I know the internals are the same, its the basic question of whats going to work better for me the 85 or 96 head. in achiving better power/economy with the carb setup.

Fuel pump will be electric anyways.

Sorry for the misunderstanding

Joe

 

In that case, as far as I know, you'll want the '85. The EFI head will give slightly more compression, but the combustion chambers are designed with a computer in mind. Both will work, but the '85 is intended for carb use.

However, if you find that the '96 is in overall better shape, you're not going to notice much difference if you use it instead.