Running a Holley 8050S (750 Vac Sec) No idea what is in it as far as jets/springs.

Problem is that the car stumbles and sputters under load, i.e. if I nail it from a start, try to kick it down a gear etc. Once it gets past the stumble, it runs like a scalded chicken. Part throttle accelleration and just cruising are fine, but dip the throttle and it stumbles.

Any idea where to start? I bought a Holley Jet kit, but it sounds like I might need to get a secondary spring kit too.

The combo, I am running:

Edelbrock Performer 5.0 Heads (1.9/1.6)
FMS 1.6 R/R
Comp Cams XE-274HR (.555/.565)
92 5.0 block and stock pistons etc
92 AOD slushbox.
3.80 rear end