I have a similar 331 combo & it makes a solid 350rwhp\355rwtq N\A on a DynoJet. Of course i have a bigger RPMII intake, 75mm Accufab T.B., 75mm Pro M meter, custom cam, 1&3\4" BBK long tubes, 2-cat BBK H-pipe, 2.5" cat-back, TKO600 trans, 4.10 gear, etc. Makes my 3,600lbs 'vert (w\me in it) fun...