I would build the 318 with as much compression as possible with stock parts. 318's are weak on compression. Mill heads and use thin MLS gaskets (0.023" thickness). Then run a Eddy Performer RPM with a TQ. Best street carb produced, but you need to find a good core. Best throttle response of any carb on the street, and tunable for 273 to 418 with secondary air valve. AVS II is a good second choice. 340 ish cam is good for a street car, but heads limit HP. Do a bowl port and match inlet side of head to manifold. Easy work with die grinder and Harbor Freight bits. Worth the time and effort. Castings were all rough from the factory. I wouldn't worry about headers on this engine, but dual exhaust would be nice and sound better.
Best of Luck with this great find.