Try getting some ole ProParts fenderwells, they almost fit with few mods, like shock tower trim on driver side and pitman arm clearance. Passenger side is close to a bolt on too, just section the #8 to get it closer to the inner fenderwell. My suggestion and it aint cheap, is to get real deal Hooker 5208's there are at least 2 sets available for 500. Not fast movers at that price but they fit. and that is just for the small blocks, weld B flanges. For 383, buy Hedman Hussler W2 for the 65, they have 1 3/4-2 inch tubes and then weld on B flanges. Cheapest and maybe the best if you can weld (or even cut, let someone else finish weld them) is to buy a kit, itll have the flanges and a bunch of 45's 90 and straights. Get yourself a chopsaw and start planning. Shoot for 1 5/8 to 1 3/4 tube size. You can cut the inners out completely and run J bars to the bulkhead and frame rail by the rad support. Then tie in shock towers. That will give you loads of room for headers. the problem with all production headers os the location of our steering boxes right under the 3-5 ports and everything usually ends up there.
