As I understand it,the 61 409's were single carb'd with small port heads There might have been a service package,Pat might know for sure,that had the 2-4 set up,but did it include heads.Unless the factory produced an intake for those heads in this case,then that package manifold would have had large port heads,thus they won't work very well on a 348[all 348's produced used small port heads].All factory 2-4 intakes were for the larger port heads .Check the forum liberary for the casting number for the 62-64 intake,it usually ends with 881 as the last 3 numbers.If that's what he has along with the correct carb numbers he has a 62 or later set up and it's worth money.