300hp magnum crate 360 convert to 380hp?

The magnum crate engines came as 300 HP or 380 HP until they stopped making stock magnum heads. They then switched over to the magnum R/T head and the ratings were 320 HP or 390 HP. In anycase all the 380 or 390 HP motors dyno'd at over 400 HP when tested.

I have heard conflicting stories as to where the pistons were different in the 380/390 HP engines compared to the 300/320 HP engines.

You can certainly swap the cam and intake and get a good bump in HP and if the pistons are the same then you would have the 380 HP motor.