Easiest/Cheapest way to a 4bbl 318?

Yes,you do it for more compression and you have to cut the intake side if the heads like i was saying.

You could just run the brand new head and use a thin head gasket.
The new heads will have been cut most likely to true them up and with the new head gasket being thinner,will give you a little more compression.
This is going to be a really good running engine because of all the parts being matched up so well.
If the compression is a little low, it will still run good for you, and make good power.
With this maybe being one of your first engines,don't go trying to make one thing really modified and forget about the rest of the car.
I would take a set of 4.10 gears over a little more compression any day.
Just fix your engine with the new set of heads and a cam\intake\carb\headers and a performance exhaust system first and see how much you have left over for a good rear end.
A stock engine with a good set of gears will keep right up with a modified motor with no gear at all.
This is something to think about.