I thought I had the 409 where it would run again but I can't get it to idle. It will stay running at 2,000 rpms but when I let off it backfires through the carb and dies slowly. When it is running it pops through the exhaust. It's got a new fuel pump and a clear filter so I can see it's getting gas. I don't have any vacuum leaks that I can find. I can't mess with the timing because of the steel governor line from the distributer to the carb. Who's got ideas?

'65 C-10, 65 L-60, 65 C-80, 72 C-60 & and a bunch of old Chevy cars.
Never time to do it right, always time to do it over.