You might look at THIS.

 

I just got it installed and it works great. I ended up using a 20lb it just barley fits in the tool box I have it set at 2 psi at the moment. It ended up costing $120 start to finish

 

Damn Nice Setup Stodg73! Love that tank. I did do alot of work for Schwann's and a few others that had Propane....and I have several old tanks....look exactly like yours, but much bigger.
If the DOT catches ya with a DOT Approved....they'll write ya up. However, the propane tanks at Lowes are DOT Approved. For Shipping, that is.
Now, theres the arguement that is a RV or a Towed trailer in need of a DOT Approved tank? If it isn't, why would a truck that has one securely mounted need one?

Well, I have a #30 mounted under my bed. I have a extra tank, so, I run out, I change it out, and its not seen. I do have a forklift propane bottle that I will eventually add once I change my bed....

 

Also with age the odometer may be off. I am running 34's and my speedo is correct. If I run 31's it's off. Get your good ole gps or use your smart phone to see just how far your odo is off. I compared my odo to a garmin on 300 miles of different driving. I get about 7% difference between garmin and my odo. This might give you good news or bad!!!!

 

never seen a first gen with a Catalytic converter. LOL Hell 75% don't even have mufflers anymore. crossy