Anyone know anything about the KL5 heads for a LQ4 6.0? They were a factory RPO option that was used to run the truck on CNG or propane.

All my research shows that they were exactly the same as the standard (gas) heads except that they had hardened copper alloy valves and seats to combat the dryness and lack of lubrication that the CNG and propane have.

Reason I'm asking is I'm going to be installing an '05 LQ4 6.0 withOUT the KL5 heads in my 1977 K5 Blazer rockcrawler and I'm going to run it on propane (ditching the fuel injection and using a edelbrock carb intake and MSD ignition controller). The rig only sees hardcore offroad use and is towed everywhere so it doesn't see a lot of miles.

I know that when using propane you need to make sure that the valves and seats are hardened but ALL vehicles made after they got rid of leaded fuel have hardened valves and seats. So, I'm not sure what difference the KL5 heads are over the stock ones. Think there'll be any problems?

Any help would be appreciated.