buckstone said:
i don't rock crawl, but even on the mild off road stuff, the 4bbl edelbrock 1403 keeps flooding. this was the carb that was on my bronco when bought it. i have an edelbrock 289 engine mainfold.
I ran a 1403 jetted for economy and had minimal fuel delivery problems in moderate technnical rock crawling at steep side angles but the carb performed OK otherwise. I don't know if it makes a difference but jetted for economy I was getting 15-16 MPG highway & 7-8 MPG on the trail or round town in my 302. Without opening up the carb I think I went down 2 steps from stock on the primaries and one step on the secondaries. I just now switched over to Mustang EFI to see if I can do better. Could be other factors influencing your mileage, including state of tune and your jetting. Of course how you drive is also a big influence.
Usually a properly jetted 2 barrel will deliver poorer fuel economy than a properly jetted 4 barrel with the same air flow. Your carb, 1403, is rated at 500 CFM. With a 2 barrel you have two large venturis open all the time. The four barrel has two small venturis open all the time and only opens the rear two as needed to get up to the flow the 2 barrel has all the time. For the same CFM, the 4 barrel is more flexible and can be tuned for better fuel efficency.
Anyway, its your $$$ and time but I suspect you will not be happy with the results unless your 4BB is really out of tune.