Realistic difference 340HP vs TTI early body headers 273

I am at the point to where all i need to finish my build is a choice of headers and since this HP 273 is going in a 63 valiant, i am wondering what the realistic difference between a set of hp340 Exhaust manifolds and a set off TTI early body headers would be. There's a set of 340 local for 400 and obviously the TTI's are going to be double that. The question is what do i get for double the price???

63 valiant
3.23/7.25
10.5/1
444/444 cam
offenhauser 360 intake


Thanks,
Jake