The large hole manifolds that I am talking about are the 96/97/98 Jeep Grand Cherokee (JGC) manifolds. The have a 2 1/8" exit hole, compared to the small hole magnum manifold that has a 1 5/8 or 1 7/8 exit hole. To compare, the 340 manifolds are 2 3/16", which is 1/16" larger than the JGC manifold. There are some 92/93 manifolds that are also large hole but they are designed differently. Unfortunately the JGC driver's manifold will not work on an A body BUT....the passenger's side fits like a glove and can be machined out (ported) to the same size as the 340 manifold. If you can find a driver's 340 manifold you can easily find a JGC manifold for 30/40 bucks!!!