I need some camshaft help. (Please)

I own a Ford 4X4 pick-up with 35 inch tires, truck 4 speed, 4:10 gearing and a 400 cid M block on propane fuel. The motor has flat top pistons with a 9.5 to 1 compression ratio but pretty well everything else is stock, including the cam.

I'm looking for a camshaft that will give me about 300 to 325 hp with the propane fuel. I know it's do-able as I know of a Chevy 350 mouse on propane that offers somewhere around the 300+ hp mark.

I would just love to get some suggestions on lift, duration and overlap from someone who knows about what I'm looking for.

Thanks loads !

viknight.