Use or don't use vacuum advance on distributor???????????????????

I found that my 68 340 S Barracuda ran best with the stock Mopar electronic distributor with the original light spring and one from the Mopar recurve kit worked great with the vacuum advance blocked off. It would have 17° anvance at idle and 36° at 2500 rpm and seemed to not have any more advance after that. It ran great that way.