Budget cylinder heads for a 318
Budget heads either magnum or speedmaster. Pretty easy to get 300hp out of the 318 magnum. The la is going to need some work to up the compression with the speedmaster heads I think maybe 9.5:1 minimum to keep the heat in the chambers.
Years ago there was a article in mopar action believe it was called small block shoot out. A little old lady had a 65-66 barracuda that had a napa blue point reman 318 with some light pocket ported 318 heads and running the mopar 761 278* advertised .450/.455.something lift and was making around 300 hp. Running in the mid 13 second 1/4 mile. With a mild 2,000 converter. Can't remember the gears