/6 Header for Duster?
I have nothing against slant 6's, they are great! But if you want power you're probably better off going the V8 route. You don't need to change your rear end if you go with a 273 or 318, maybe even a 340. My Barracuda Formula S has a 7 1/4" and it's doing just fine behind the 273. You can find a 318 with a tranny attached for a lot cheaper than the money you'll put into your /6 trying to make it go fast! Just my opinion......