Not true,The max wedge haeds just have bigger ports.Also A&A transmission is the one that repoping the manifolds for mopar.They make two one for the 440 and one for the 426 wedge.You can take any RB manifold and make it a max wedge or any head and make it max wedge.The only thing that don,t fit is the valve covers.The max wedge valve covers has 4 bolts to hold them down.I am not talking about the indy440-1s or B1 heads. Mark