The 155 hp is factory rating which is typically a little low. My engine will now breathe a lot better with all of the emission restrictions removed, headers added and free flow exhaust. Also with fuel injection you can get the fuel ratio better which helps also. So assuming I’m somewhere near 200 hp is not implausible.
Some are paying too much attention to the 400 hp and not the thread title. Best way to increase hp in my 318
Alright, so you may already be near 200 but have not confirmed that. I'm not so sure that mopars have emissions hardware that really impede airflow, but if you have changed the intake and added a 4bbl, headers and duals, then yes, you have probably improved pumping capability.
Still recommend trying to find the cam specs, determine what casting heads you have, and taking a cylinder pressure reading. Knowing actual cylinder pressure is much more helpful than a published compression ratio. The factories have demonstrated a wide variance in actual ratios compared to advertised ratios. Knowing the year of the engine, as pointed out above, may help with this. All of these thing can help determine if a cam change or head change is going to be a negative or positive impact on cylinder pressure and power output.
If you don't mind throwing money at it, then you can just start changing things and backpedaling into the corrections to fix what you just changed. I'd recommend against this approach.
