[OE Espo]

Helping someone work on a 70 Lemans Originally equipped with 350 2Bbl. Have build-sheet and under 40k original miles.
Doing some research probably (guessing here) has a 254 camshaft .375 int .410 exh. Has No11 heads. Believe its a 2.78 open rear.

Want to wake it up some this winter but probably in stages.
1. Winter plan replace 11 heads with 13 (have them). getting them cleaned up. they dont have springs OR rockets in them. considering keeping cam now and using 1.65 rockers. no port mods. hoping block is chamfered for larger valves and just increasing ratio that we wont have any valve interference.
2. Add 68-72 iron intake (have)
3) Add quadrajet

Thinking these mods alone should get better seat of the pants feel.
Future considering 068 cam, 3.23 rear posi Want something for highway trips

Should i get heads milled to more like 350 HO #48 heads. had one in my car it ran great. if so to what cc?
other camshaft recommendations?
rear gear recommendations?

thanks