I'm replacing the stock mechanical fuel pump with a new one, which is supposed to work with my engine. When comparing the new and old pumps, the lever/rocker arm on the new one protrudes about 2mm less than the old pump. It's also a different shape. It looks like this is the case for all aftermarket mechanical pumps I can find.
I intend to go electric at some point, but not until I buy a new carburetor. Will this 2mm difference stop things from functioning? Would a longer push rod help? Should I shave 2mm off the fuel pump spacer? The new and old spacers are exactly the same diameter btw.

Any help is appreciated, as always.

I can't figure how to post a photo, but here' a link to the two pumps side by side:
http://img.photobucket.com/albums/v4...psmicrgdiv.jpg