I looked at a used f450 02 I think I was a crew cab xlt 4x4 and it had cng and unleaded with a v10.
Looking back I should have bought it. I still see it getting used daily by a local landscape company. And all there trucks are v10 cng
A buddy of mine picked up a used F150, around that model year, or just a bit newer. Factory CNG/Unleaded, was a British Columbia Highways truck. Loves it. Power is down slightly on CNG, but driveability is still fine.
Given BC's lunatic gasoline taxes, it is his favourite work vehicle to use around Greater Vancouver. They haven't built any roads there in about 50 years, so paying for gasoline in a work truck that spends most of it's life stuck in traffic was killing him.
I like CNG as a fuel, but until the infrastructure matures, I would want a dual fuel platform for personal use.
Rgds, D.