318 build!

Find running motor, bolt in and go. Probably the most economical way if you are on a tight budget.

Cam wise, a stock replacement 340 cam works well in a 318 using stock heads and compression. Cheap too. Otherwise a Comp XE262 or so would be about the most I'd run.

I would avoid a single plane intake unless you already have one, and only then if its an old Holley Street Dominator. A regular Edelbrock Performer (eBay) would do much better. Carb wise a Holley 1850 or Eddy 1406 would fit the bill.

You say you're on a budget so the best thing is not to goo too nuts. If you can find one, get a Magnum motor and a carb intake.