Get yourself a custom burned flip chip for the propane. Go with a Jody Tipton or a Tony Wildman chip. Those that don't understand propane are usually scared of it. Do your homework and you will be fine. I have been running Propane for awhile and not have any problems.
As far as racing a 4 ton truck, there is just something about the looks on the faces of unsuspecting people when you leave them in awe because that 4 tons truck just smoked your A--.