My wagon, 4600lbs, 526 inches, unported rpm heads, 10.6 compression, mild cam. 2600 stall, 3.73's.
had a rpm w/ 850 holley. ran ok. changed to an M1, and a 1000cfm 4150 quick fuel carb.
HOLY CRAP. a difference of night and day. car feels like an animal now.
go with the M1.

526 cubes of angry wedge, pushbutton shifted, 9 passenger killer!