You’ve left out some important information that is needed to make any really meaningful recommendations. That being what do you want the truck to be able to do once you get it built. Is it going to be an in town cruiser, is it going to be used on the interstate, etc. What kind of compression ratio are you looking for (do you want it to run on regular or premium fuel.

In generalities I would probably go with one of the 350s just for the cubic inches. Chances are both are going to need to be bored, so it probably really doesn’t matter which one you use.

As far as heads go the 397487 are a pretty good large chamber choice. I would stay away from the 3947040s which are a smaller chamber head that will make more compression, but the big down side on these heads is they don’t have the accessory bolt holes which may make finding bracket a problem and possibly pricey.

I like the 700R4, but would really relook the rear end ratio. With any of these cylinder heads you’re basically looking at 1960s cylinder head tech. Depending on the cam you choose, these engines have a happy spot when cruising of around 2700-3200 RPM.

There a few different OD ratios for the 700R4s, a common OD ratio is 0.69. With a 3.08 rear gear the effective rear ratio becomes 2.13. With that in mind and depending on the tire size, chances are the engine will be lugging when the transmission shifts into OD.

The deeper the rear gear you use, the more fun the truck becomes to drive (just an old hot rodders opinion LOL). From personal experience one of the last rods I built used an OD transmission that also had a 0.69 OD ratio. I was running 4.56 gears in that rear end and in OD ( effective ratio 3.14) with a lockup convertor it would comfortably run at 75 MPH with the engine turning around 3000 rpm. I’m currently building a car with an OD transmission that also has a 0.69 ratio and am planning on using 4.30 gears (effective ratio 2.96) and a 28 inch tall tire.

Just an old mans 2 cents, and welcome to the forum.


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