dual action fuel pump

[Charlie ny]

LC,
The early pumps have the small mounting face whereas the 8ba pumps
single or double action pumps have larger (longer) mounting face. The double action pump
versatility comes at a price, in my opinion, that price is a very stiff action. Speaking
for myself I cannot actuate a freshly rebuilt pump by hand. Often times when
I get a car so equipped in the shop I find the push rod is bent. JMHO !
Charlie ny