Technical 72 850 spider acceleration issues

[TNmtnBoy]

I have a '72 850 Spider that will barely climb a hill even in first gear. Once on flat ground it accelerates and takes off. Hoping for some advice on what to do next.
Here's some details and what I've tried so far:

Car has a "mild" replacement cam.
Recently rebuilt head.
Rebuilt 30DIC carb, torn completely down, jets cleaned, rebuild kit installed. NA market smog stuff has been removed and capped off.
I have only used non ethanol fuel in it.
New Facet electric fuel pump and filter. (had this acceleration issue prior to the electric fuel pump install, but condition seems to be only slightly improved since)
Idles at 2000rpm adjusting the idle screw seems to only barely affect it.

I am wondering if it could be a timing issue, or possibly a carb issue? Any suggestions would be most appreciated. Thanks!

 

[Gary50]

Hi
Make sure the Facet fuel pump is placed right down at sump level (if it isn't already).
I had a similar problem with my 900T when I added one... these pumps don't have enough power to suck up hill (and struggle in any case if placed much above the bottom level of the fuel tank.
Hope this helps.