Flow tested a few carbs the other day, thought I'd share my findings. The Ultra HP carbs are the older design from around 2005 they are no longer sold.
Holley Ultra HP 750 part#80675
1.375 venturi / 1.687 base plate
819 cfm
Holley Ultra HP 950 part#80676
1.375 venturi / 1.75 base plate
825 cfm
Holley 850 "old style main body" part# 9380
Choke horn milled off, slabbed throttle shafts, annular boosters
1.58 venturi / 1.75 base plate
945 cfm
I'll be replacing the 1.375 main body of the 950 with a 1.45 main body and retesting in the coming weeks.
This test backed my suspicions about the true flow of the 950, as it was only able to make about 5 more HP than the 750 on an upper 500 HP 360 motor. 950 my *** lol, I know Holley took a lot of **** over that carb and the new XP950 has a 1.6 venturi because of it.
