Dogdays gave the best answer yet IMO.
Also, IMO, the 318 / 302 heads up top the 318 was OK IF well ported. If they were stock, I suggest firing the machinist from any performance work in the future. The 360 out flows the 318/302 head by a lot. It takes a good bit of porting to get the 302 head to
Perform better than the stock 360 head.

As mentioned above, look into a better head made of aluminum. Better flow, lighter weight, better material, larger valves and a better spring selection with greater lifts available to you. All OOTB better for comparable money.