318 LA hp and torque question

If the 69 318 uses the 920 head casting, it's a wash on compression using the 302 head.
They both have the same volume. The book lists '69 318 with 9.2:1 compression.
That's the same spec as the roller cam, 302 head motors.
The gain would be hardened exhaust seats, but the size of the valves IIRC is the same.
...and perhaps the "swirl".

That 268 cam is kinda peaky for a street build.
One or more steps "down" is more tq earlier and not much HP sacrifice.
I think the 340 cam is right on target.

I agree with duals being the best first mod.
That's what the factory did on 318 Roadrunners, and said it was good for 20HP.
Headers are a double edged sword. Esp small block headers.