flathead on gas

[midgetracer81]

Look for info on building a flathead to run on gas will have purple plate which cam to run ignition timing and jetting.

 

[Jon Brogden]

Run any of the stocker cams recommended for purple plate, whether it's a Dyno or Percision or whomevers, fuel isn't a factor for cam selection. When it comes to ignition timing gas won't need much advance, probably a #2 key at the most. Jetting I'd have a stock jet, which is .036 and a .038 maybe a .040 the restrictor cuts back on fuel signal so you generally need to go bigger than you would without the restrictor, but I've never tuned a purple on gas so I'm not sure how much it's gonna want. On gas the needle setting makes a big difference. Jon

 

[alvin l nunley]

.036" to .040" is a 23 1/2% change in jetting. That's a bunch. Not saying it's not right, just letting you know it's a big change.
36
37 +5.599%
38 +11.395%
39 +17.387%
40 +23.477%


From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.(Al Nunley)

 

[Gearhead]

I built a few with/and liked the Dyno 96-3 cam in it, 24 degrees ignition timing ,and a stock jet , ran good and kids won a few with it. I liked building the meth purples better than the gas purples .