What are some things I should do on my engine for dual fuel?

I don't want to have a backfire or anything breaking.

I hard a metal PCV valve and a 81 degree thermostat instead of a 91 degree thermostat.

Anything else?

You dont have to change the PCV itself, you just have to re-route the line that runs from it.

You can buy an adapter that allows you to run the line to under the Idle Speed Controller. The adapter cost me $47 from a LPG Supplies store (M.E.D in Villawood)

That's all that I have done to my car when we fitted the LPG to it. I have had it in the car for 6000 kms now, and has not backfired once