Does anyone know if it is possible to modify a ford flathead 6 diaphragm single action fuel pump (similar to the flat 8) for increased volume and/or pressure? I am wondering if changing the spring would have any effect?
I doubt, ( but not sure), that swapping springs would help...............................Early mechanical pumps, were modified, to be "boost referenced", on blown engines, by porting the "boost reference" pressure, to the top side of the diaphragm............. I'll be listening in.
OK thanks- I will probably switch to an electric pump (carter 4070), but just am stubborn and didnt want to give up on the stock one!
For pressure, the big spring under diaphragm controls things. Early Ford ones are very soft, one form something like a '60's Chevy will be higher pressure. Many pump parts interchange within basic sizes of pump. I think total stroke, presumably limited by amount of movement at diapragm, would control volume and would not be easy to change. I think only practical way there would be to find one of the physically larger pumps with a flange that fits your engine and convert it to the rocker from old pump...if that's possible. Now...something to check out...I have heard (no actual knowledge) of replacing everything from diaphragm up on a flathead pump (same upper works as yours, I believe) with the entire top of a 6-valve Corvette pump to build a high volume unit. Never owned any parts for that so never tried anything like it. Standard route for higher volume on a flathead was the somewhat rare Bus pump, which useta was sold through speed shops. Physically larger pump for normal flathead mounting.
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