5/16″ or 1/4″ Hard Line? What works on my Stromberg 97 carbs?
We get ask a few times a week, 5/16″ or 1/4″ hard line for my Stromberg 97’s. Stromberg launched some fuel fitting kits so you can make 5/16″ fuel lines for Stromberg 97s. While the stock early Ford 1/4″ OD hard lines are great-looking for a typical flathead motor, many people like the thicker lines for Chevy’s and other applications.
Stromberg 97 S-jet inlet valves (needle & seats) were originally designed with a 1/4″ pocket to take the fuel line. The angled seat positioned of the brass ferrule can only compress properly to seal on the 1/4″ tubing. You CANNOT use 5/16in OD hard line. If you do, the line does not sit deep enough into the fitting and, worse, as you can see in the picture below, it covers most of the ferrule sealing surface.
When using 5/16″ hard line, you need our 9564K-BIG S-jet inlet valves and a pack of 9081K-BIG ‘Ford Nut’ style compression fittings. These are designed specifically for 5/16″ line. Assembly is then just the same as it would be for a regular 97 with 1/4″ line.
In summary:
FOR 5/16″ hard line USE 9081K-BIG 5/16in Ford Nuts AND 9564K-BIG S-jets.
FOR 1/4″ hard line USE 9081K 1/4″ Ford Nuts with standard 97 S-jets 9564K
9564K-BIG S-jets also work with 9080K Superseat hose ends.
One more point. DO NOT use the Stromberg 9182K 1/4″NPT hard line adapter for 5/16in tube into the 97 S-jet or needle & seat as the tapered NPT thread won’t fit or seal. The S-jet thread is 1/2in UNF.
