Well if there aren't two collectors then my only recommendation would be to call a vendor before you buy and see if a 99 and older manifold will work. It should mount the same way, the only thing I would be concerned with are the exhaust ports and the location of the downpipe.
2011 Dodge Ram 1500 Big Horn 4x4
5.7L V8 Hemi
"The Tow Rig"
2001 Jeep Cherokee Sport
4.6L Golen Engine Stroker
6.5" TnT Customs Longarm Kitl Ford HP D60 l 6.5" Rock Krawler Coils l TnT Customs HD Trac Barl Omix Ada HD SYE l 1" UBEsl CV Driveshaft l39.5" IROKsl 17x9" Pro Comp 98sl High Clearance Shock Mounts [COLOR="red"] l Hidden Hitch l AJs Custom Front Bumper l SONY Xplod stereo l Alpine Speakers l TnT Frame StiffenerZ l 22" RE SS Brake Lines l 1.5" TnT Customs Boomerang Shackles l Sterling 10.25 *FULL WIDTHS* l JKS Mini Skids and Sway Bar Brackets l 7/8" Heim Joint High Steer