Sounds like you don't have enough volume. I found this:
http://forums.corvetteforum.com/c1-...5-hi-volume-mechanical-fuel-pump-testing.html
About half way down the first post he mentions how much fuel you should pump for a given car. He's talking faster, more powerful cars, but it seems you're right, the 60 gph you're seeing isn't enough.
New parts don't mean good parts. Go through your delivery system closely.
I don't have anything running to do a test on. You know anyone whose car you could test to compare?