I have a 79 bronco with a 400 running on propane with a 425 impco,what would be the proper plug and gap?? also any input on initia+ total timing ???vac advance or not ???

 

im not sure about heat range for your plugs. you might want to get onto a propane conversion site and see if it calls for colder or hotter plugs.

initial timing is usally set as high as possible w/o detonation. when it pings, back it off. i'm not sure what you would need for total timing, but if your running the stock dizzy i would say that it could probably use a set of lighter springs.

vacuem advance is the way to go for a street vehicle that needs to get decent mpg.

i will look into some of the info that i have.
tell us how stuff turns out...

 

Run on heat range cooler with the same gap as stock.
Timing, I would recurve the distributor to give you more initial and less certifugal advance. At least thats what worked on my turbo propane El Camino....

 

i am going to the wrecker this wekend and was hoping to get some spare weights and springs of different rates for the dizzy, just hoping to get some solid numbers on what total advance so I would know what weights to get...