318 LA hp and torque question

YY1 said
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.

YY1 is correct. My 69 318 Barracuda came from the factory with 9.2:1 CR (by the factory manual). When I swapped out the stock heads for 302 castings I found that the original heads were 69CCs, when I checked the swirl port heads they were also 69CCs. The pistons were .039 down in the hole (the tallest piston they put in a 318). I was hoping to get a little more power from the swirl ports but the main reason was for the larger exhaust sealing surface for the 340 driver and 360 magnum passenger exhaust manifolds. The old original 318 heads have almost no sealing surface on the bottom edge of the exhaust port relative to the large 340/360 manifold ports as shown by the big difference between the stock 318 exhaust manifold gasket and the 360 magnum gasket. I've read that you can get the stock heads to seal but why take any chances when you have a set of swirl port heads sitting on the shelf saying, "use me...use me!!"

Treblig