The 365/375 horse 327 had a cam in this range. Speed Pro still sells it. Put it in your 318 along with a nice intake and carb and some headers and see where you go. I bet that 327 had 10/1 compression at least which the 318 lacked. A 300° cam is pretty nasty especially in a small cube engine.
Speed Pro # CS118R 254°@ .050 295° adverttised duration
.485 lift 114° Lobe separation.
The Chevy guys say it comes on strong at 3500 to redline. (no idea what that is but guessing 5500+)