New to me 73 duster 340

Sorry about your loss. I'm sure that car meant a lot to your grandfather I hope you get enjoyment out of it. First of all almost all 340s that are anywhere near stock will never need more than 36 degrees of total timing. I would next be looking at fuel delivery. floor it does it backfire that will tell you it's leaning out. Another thing is you mentioned stock gears but does that mean exactly 323s 355 391s all were available if it is higher than a 355 and you say it's cammed it's probably not a good match. Especially on a low compression 73 340.