318

Rear gears are very important to know when it comes time for chosing a cam.

The 318 block can make great use of Keith Black pistons. Keith Black (KB) has come out with a flat top piston that can sit at zero deck height. This will provided an excellent compresion ratio. Head gaskets thickness plays a part.

To bolt the rest of this engine togther on the cheap, the following paths should be considered. All is dependent of your time frame, wallet and how long your willing to wait for the part.
At zero deck (pistons w/5cc valve relief) and 360 open chambered heads (72cc's) and a Fel-Pro gasket @ .039 thick and 4.1 bore sized gasket, the comp ratio will be 8.63.

Removing 5 cc's from the head will up the ratio to 9.1. Excellent pump gas ratio. You should not exceed 9.5-1.

Cheapest...........

A set of 360 heads, factory 4bbl. T-Q intake and T-Q. These can go cheap at a swap meet.
Open air cleaner, cam of your choice that should operate in the cruise rpm of the car. 1,000 - 5000 rpm or 1500 - 6500 rpm's.
In an example, a comp cams kit can provided just about everything you'll need to set up the cam and valve train.
Go to a cam's web site and read up on the suggested RPM range of the cam, where cruise is.
For a car with pep, I'd look at the XE268 hyd. cam.

With exhaust manifolds, this should be an easy 270 HP and about 300 lbs of torque. Give or take a few here.
Headers can add well to the package. I'd put it up at 330 HP and 350 Tq.
Again, give or take a few.