A engine mechanical fuel pump question

[IMNCARN82]

I'm trying to figure out why this 360 isn't running right.   Only thing I did was a new fuel pump. Was a pain to get it in.  Could it be wrong?    Maybe the arm isn't in right.  Just a thought.    Anyone have any insight?   It will start and idle. But I can only bring the rpms up slow. Everytime I give it gas she acts like there's nothing there. pops.  kinda backfires.   weird.     I worked the pedal so much now there seems to be a fuel leak at the acc. pump or where the linkage arm comes out. Edelbrock 650 not that old.      Drove it in 3-4yrs. ago. Didn't touch a thing other than that fuel pump.  Hmm.     

Thanks for any help.

R/T

[Bullitt-]

Sounds like you may have identified the issue already.. Carb accelerator pump... or the circuit is clogged. Carbs sitting dry out.

get ya one of these better pump diaphragms while your at it
http://quadrajetparts.com/carter-accelerator-pump-double-1316-alcohol-resistant-p-770.html

[jimynick]

When you put it in, the body should be tilted up somewhat and it comes down flush when you tighten the bolts. That makes sure the arm is under the fuel pump eccentric on the cam. Plumb a gauge into it and see what you've got for pressure before you get into the carb. 

[cudabob496]

backfire can be timing

[dave73chally]

What psi fuel pump did you put in? Maybe it's flowing too much gas to the carb, running rich and backfiring. I agree on the pressure gauge. If all you changed is the fuel pump I'd think it's that...