Realistic difference 340HP vs TTI early body headers 273

Considering how much trouble the header-install is on those early A's, and the 273 power level, and the $ difference, I'm leaning towards the early HP 340 manifolds(68 to 70?), if they sneak by the steering column.But do you know there's a guy here on FABO that can supply big-mouth Magnum manifolds? He supplies them all cleaned up, and ready to install. search Trebleg.