Realistic difference 340HP vs TTI early body headers 273

Treblig does the manifold modifications. Here is his thread.

http://www.forabodiesonly.com/mopar/showthread.php?t=286272

He does a VERY professional job and is a stand up guy. The Magnum manifolds come stock with 2.125" outlets. Plenty big enough and since they are Magnum manifolds, they flow very free. Plus he does all his tricks to them and makes them even better. Read the thread. He is a good dude.