Cheapest ways to increase power

Relatively easy things to do ; mill head for 9.25 to 1 compression ratio accounting for new headgasket, 2 barrel intake with Holley 2280 or Carter BBD, gasket match the exhaust manifold at the outlet, 2.5" downpipe to hi-flo muffler and 2.25" tailpipe, recurve the distributor. My '72 4 door Valiant with 225/auto and 2.76 gears went low 17's in the 1/4. Over all driveability was improved. My next mod would be oil control in the Pan to reduce windage.