i think people were expecting or led to believe they were going to get a bolt on 600 hp head or a head that would blow the edelbrocks away but that didn't happen .
Eddy sbm head is nowhere near in flow/performance to the TF's, they are only a bit better than a stock iron head.....most think they can bolt a TF head on with a .495" hyd. cam and make 600hp@5500rpm with 9.5:1CR..not going to happen....TF190 does blow an ootb Eddy away and IS a bolt on 550>600hp capable head if you put it on a proper short block with enough Comp, a cam that takes advantage of all the flow and a big enough carb/intake/hdrs etc., but how many build a motor like that for the street, even for street/strip.