I'd go with the spacer since you already have it, make sure to double check hood clearance though, somtimes that extra inch or two will make it too close to the hood and hender air flow.
Not trying to hijack this thread here but I gotta a similar question.
I've been running my carb flat on the intake, I've been contemplating using a aluminum or plastic spacer or one of them supersuckers but I'm somewhat reluctant as they are kinda pricely.
Motor is 496 BBC 13-1 compression, 722 solid roller, carb is 1050 dominator, dart single plane.
Do you think I'd benefit from a spacer? if so what size 1, 2 inch? Open or 4 hole?
Thx, Cp