One thing I would look at the need for when doing a CNG conversion is hardened valve seals.
I work for a truck equipment manufacturer and one of our large fleet customers recently wanted to convert part of their fleet to CNG bi-fuel service trucks.
They decided to go with 2012 Ford F-350s, SRW, 137" WB, 6.2L V8 Gasoline.
When their fleet advisers were discussing the process of the conversion, they said that to extend the life of the engine, they would be pulling the heads off the V8s and installing hardened valve seals. I vaguely remember him explaining that a standard valve seat engine would last 100,000 to 120,000 miles and that an engine with hardened valve seals would last up to 250,000 miles.
Just thought this may be helpful for people who are seriously looking into a conversion.
