I thought the d4b intake was for the 64-65 heads only mine are the odd ball 2 year only heads the high reving was for the short distance and deep gearing so that it wasn't running out of top end super fast and to not have to **** every 2 seconds the stock bore pop ups was inspired by the super stock 273 from 1966 d/dart the engine build was a mash up of all the pros of performance build ive grown to love growing up and hearing about