Chris,
Don't know anything about the mallory unit to offer any help. However, I do think you would want a "retard" type box.
As Duane stated, the super-suckers are the cats ass for the victors! They really even out the flow down the runners. I've always had problems with the back two cyls running a little more lean than the others.
One of these in a 2" version with a 2" spacer ought to work great.
ken