Mike, with the twin blade base plate, are the bore centers the same as 4150 stuff (same bore centers, just opened up to two slots) or something completely different?
Cheers
Alan: There are 2 different sized baseplates. The 'smaller' version has the same footprint as a Holley 850. These carbs vary from 650 to 1230cfm, depending on main section/booster arrangement. These carbs will fit any 4150 or 4500 intake manifold.
The 'larger' baseplate size is between the 850 and a 1050 Dominator with an opening of approx 4.375" square. These carbs vary from 1200-ish to 1620-ish, depending on main section/booster arrangement. These carbs will bolt onto any 4150 or 4500 intake manifold, however if used on a 4150 manifold, the opening will need to be enlarged.
