the saddle tank down the driver side inside frame is the pisser for duels..they have to run over to the pass side then back to the axle,up and over then split to each side.

I just removed my duels like this and moved the tank to the rear by using a 69 mustang gas tank, the sender work a dodge fuel guage and it mad room for a nice short set of 2.5 duels turn out in front of the rear tires

for headers you will want the hedman heeders 79080 they are low cost and fit well, have the ball/cone collector down low for no leaks.

the hedman 79170 will work also and are 2x & 4x4 headers.

if you where closer I have the headers, pipes with collectors bent to go over to pass side and back with 2-10 yr old 2.5" glass packs that sound really good. that's 1/2 of a set of duels still in good shape.