LA 360 budget build ideas

Car is going to be a semi daily driver as weather permits. My goal for the car is strictly a cruiser ( looking at getting a 1973 duster ). Gas mileage isn't a huge concern but yet I'm for better than 5mpg. Rear gearing, I thought about either a 3.23 or a 3.55 gear ratio. I don't want the engine spinning at 3,500 rpm's at 70 mph. If I need to change the torque converter that's okay. Are mopar small blocks known for coil bind with cams over a 0.515" lift? I thought about running the pistons at zero deck height, with a head gasket that has a 0.039" compressed thickness and 1.880" intake valve's, will I have piston to valve clearance issues? Do I need to run closed chamber heads? I'm wanting to select the right parts so that my combination will work well. Also, if I was to buy bare cylinder heads are the seats already cut for a certain size valve? Since my goal isn't 400+ horsepower I was thinking of using 1.880" intake valve's and 1.600" exhaust valve's with a comp valve job and back cutting the valve's, bowl clean up. Am I going in the right direction or am I totally wrong?

Pretty much a quality build with 9:1 compression ratio. 340-360 milled .020 LA heads with bowl clean up, very good valve job, tight guides, viton valve seals, back cut intakes, 1.88 intake valves are fine 2.02 better, 340 or equivalent valve springs. Good intake, 750 cfm carb, Hone with torque plates, balance the rotating assy, file to fit rings, windage tray, high pressure oil pump spring, double roller timing chain, 268-276 duration, .450-.500 in lift cam. 323- 3.21 gears, That is all it takes.