Found a 4vcast cast iron manifold off a 1966 model 390 onCraigslist. I'm assuming from a car. Will this work on my 72 f100? Also, will an edelbrock or holley carb with a square bore fit it? What should I look out for buying a used intake?

 

Yes. It will fit. Be mindful of its fittings in case your rig has any required emissions.

A square bore manifold will fit. If the owner has the Autolite 4100, I'd pick that up in a heartbeat. A 1.12 stamping on its side means 600 cfm, a 1.08 means 480 cfm.

When buying a used intake, check for damaged threads, cracks, and warping. If it has been bead blasted, make sure you clean it thoroughly before installing it... some manifolds have little nooks and crannies that can hold/hide media.

If you're in the aftermarket, the Edelbrock 2105 or 7105 is a nice piece... saves a TON of weight too.