My build is similar to yours - 73 Sport 340, Eagle crank with H-beam rods, JE flat top pistons, decked, Edelbrock heads, RPM Air Gap intake, 750 Holley, Schumacher headers, 3.91 Sure Grip and Chevy 200-4R trans. 1.6 roller rockers. I got with B3 Engines for their geometry correction kit for the rockers. This is the cam I'm running, a solid flat tappet - Comp Cams Xtreme Energy 244/252 Solid Flat Cam and Lifter Kit for Chrysler 273-360​