More power from my 360 Duster?

without pulling the heads,id say your cam is small,i would upgrade to a lunati voodoo,slit pattern cam,will help wake it up some.Also,the cam is a bit small,id go with a 750 holley,vaccum secondary.Get it jetted right for your combo,and work with the secondary springs to get it dialed in.Other than that,you could pull the heads for some porting,and gasket matching to the intake.All those things combined will wake it up the most,without upping the compression,still be plenty driveable on the street,as long as you dont pick the biggest cam