34 manifold to stock 32 engine

[dodgeo]

Changing the manifold on my stock 32 original engine to a 34 so that I can
run a 2 barrel carb and a better fuel pump.
Question; I bought a new fuel pump rod described as for all V-8's with an
aluminum manifold that is 7.87 inches long. It appears to be too short. My
original push rod is about 8 3/8 inches and looks like a better fit.
What should I be using ?
Thanks for your help with this conversion.
Dodge