My 85 F150 has an Offy dual port intake and 450 cfm Quick Fuel carb. After tuning it idles great, but I cannot get rid of the stumble when shifting between gears. Has anyone experienced this? Have ideas/suggestions how to fix it? It’s so frustrating I’m thinking about going back to the old intake and 1bbl carb.

 

If anyone is interested, I figured out the issue. The Offenhauser dual port intake has the primary ports facing the valve cover of a 300. That makes the proper orientation of the carburetor such that the throttle faces the firewall. My was not orientated that way, and couldn’t be turned the proper way without making a pulley system for the throttle cable, because the blower box is directly in the way. I switched to a c series Offenhauser and my problems all went away!