360 heads flow better, but you'll die on the street unless you set the engine for high rpm duty. It would be a better idea to put 318 heads on a low compression truck 360. You need compression and you need quench to get this for a street mill.
Correct!!!!!! The 360 head has a large port for a mild 318 which will cause the air and fuel to be slow and hurt power.
Conversly the 318 head on a low comp 360 is a great idea for added power and torque on a low RPM engine. It'll speed up the air and fuel real nicely and burn better since it is being atomize finner. A 302 head will add a great quenched area to boot.
The RPM will have a lower ceiling, but it isn't a big deal for a truck/tow/work ride. If fact, I think it a good one.