Which cam is the closest to the factory/Isky cam used in E Code Racing 285 HP engine applications?  Will an Isky E4, RPM-300 or   F-300 provide 16" of vacuum at 1200 RPM?  What would be the best performing cam for a .060" over E Code 312 with factory exhaust manifolds and 4.11 or 4.57 gearing?  I'd like to retain my factory valve train, tubular push rods, springs, etc., if OK.  Would new lifters from Schuman be the best for any new cam?

Paul J. - '57 E Code