honestly 350 to the wheels will be a fairly aggressive 306 unless you turbo or supercharge it, the 150 shot can possibly get you there but you will be bottle dependant, did that for several years myself (175 shot).
everyone claims to make that kind of hp na but really you need some compression, a nice matched heads/cam/intake and several supporting mods to get a realistic 350 hp to the wheels with decent driveability.