Drove Ol' Roy to work today and covered the same stretch of road where the backfire first manifested itself. I didn't lose power up the long grade and it didn't blow a stinker when I reached the top.

The carb float pin hasn't fallen out so I must have installed it in the right orientation.

Truck is getting its usual 12 mpg so it looks like everything is back to normal except for the following issue that didn't exist prior to all of this nonsense.

1. When I remove the gas cap, it is vacuum sucked to the filler neck. It is a one year old, vented Motorad cap - the same one sold by everybody, including under the Gates brand name. What happened? The tank is not pressurized. A vacuum is being created in the tank, I assume by the fuel pump. What should I do about it? Drill out the purge valve on the underside of the gas cap?

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)