It's easy to tell a 1920's to 1950's Fuel pump diaphragm from the new ones- back then the only material which could stand up to gas and still flex without stretching was 3 or so layers of tar-coated canvas. Picture attached
Today's gas takes that tar right off, in our test 1952 stored till 2008 About a gallon's worth!
Using a make shift rubber from an innertube ran for 1 day...for it's madden tour on June 2 ,2008
before returning to a leaky mess.
Best solution 12 Volt fuel pump run on 6 Volts with a power up converter. (future project)
Buna-N Nitrile rubber is the industry standard for a fuel diaphragm. 2008.
Today, we run on Nylon re-inforced "Neo-prene", purchased by part sheet at Industrial Rubber inc. Winnipeg
Listed as 'good" for gas but NOT excellent Buna- N Nitrile was avaiable in winnipeg but not re-enforced for use
as a moving diaphragm.
Never mind running, you don't want lines, fuel pumps and carb's to leak (at all) in an attached garage.
the fuel line system is vital and needs to be re-worked, item by item.