318 heads on a 360

4bbl 360s were born at 240RWHP, back in 71, with nothing but a 340 cam, and an advertised compression ratio of 8.0
After headers, and a timing adjustment, she'll be chasing 300.
But just remember, this horsepower does not arrive until 5000rpm,44 mph with 3.55s, in first gear. But to reap it, you gotta get there first! So if the combo is a slug below 3500/31 mph, where say 95% of your driving will be done, then do you still want 300plus horsepower? Well, with a 2800TC, she won't be that much of a slug off the line,lol. But the point remains, that the power does not show up until ~44mph.
What you really want is torque lots and lots of torque. With a normally aspirated engine, there are about two ways to get it;
1) cubes, and 2) cylinder pressure.
Cylinder pressure is a balance of Static compression ratio, and Intake closing angle, against the ability of your gas to resist detonation.
What that means is; A) if your engine has a low Scr, then it needs an early closing Intake, to make pressure. The more pressure she makes, the more torque she will make, until the engine hits the detonation wall. But B), if the engine is a hi-Compression unit, then the Intake has to close a lil later, to prevent detonation from too much pressure.

The definition of horsepower is;
Torque x rpm/5250= hp
So, to make lots of hp, you just need to create lots of torque, hi up in the rpm band. And the cam unlocks this by moving the hp up or down the powerband.
Like this; say you had an engine that made 300ftlbs of torque at 5250 rpm; then
300x5250/5250=300hp. Say you then changed the cam and moved the 300ftlbs up the powerband to 5450;about one camsize, then
300x5450/5250= 311 hp.
That is how you make hp. Of course the rest of the engine has to support the new rpm, to achieve that.
But, with no other changes, that bigger cam is gonna cost you about 6 or more psi cylinder pressure on the bottom, which could represent 6 or more hp off the bottom, depending on your stall-rpm. If your pressure is already very low, then this sucks, and costs you the next bigger TC to overcome. The loss is still there, you just never feel it anymore.