Have you done a cost/energy balance to see if its even fesable for propane to offset fuel costs? You have a Cummins which will hold up alot better than most other trucks, interms of high cylinder preassures. For me it was not cost effective. A kit costs about 500-700 dollars, and then you need a tank and then your install time. Your looking at about 1G for everything. Then theres is the cost of propane which for me to fill a 5lb bottle is about 15 bucks. How long will that bottle last, is beyond me I never got that far, cause It was uneconomical after spending 1G on the system. Now i just make my own fuel
