carb spacers

I have a mild rebuild on a 65 Plymouth 383 HP, auto/3:55 gear,Eddy performer intake, question: are the carb spacers for top end performance only or would one help for average cruzin???

thanks guys

4 hole may help your bottom and the open spacer usually will add to the top. Not a set in stone thing but usually.

and sometimes an open spacer will make a handfull more hp on the topend, but will take away tork on the bottom.....which, unless you have a stroker, can have negative effects on et, as opposed to not runnin a spacer at all.