edit: I know that you know this, but i'm posting everything I know for future ppl too. sorry if I sound cocky.
little ID on the carb, It looks to be an autolite 1100, with manual choke of course, here's a pic of the
pony 1100 which has an automatic choke
you should have 3 total screws, 1 cold idle screw, 2 idle screw, 3 gas/air idle screw.
here is where I think they are on your carb from the picture you posted. try adjusting them and see the changes.
A LOM distributor only uses SCV, and will not work with manifold vacum.
I still have this exact setup, 1100 carb and LOM distributor... here is what I would do without a timing light.
1) make sure the vacum can on the LOM is working, BLOW don't suck unless you want alot of fumes, and see if the engine rpm changes, if yes then it's good, if not you need a new one (i've found napa has them readily availible) If it can't hold air it's popped.
2) with vacum disconnected from distributor can, set idle to pull 19.5-20 FROM the manifold, not the carb scv, this was the BEST on my old stock engine (recently replaced)
3) raise idle SCREW to ~850rpm, THEN change idle gas/air ratio screw to run the HIGHEST rpm you can get.
4) lower idle SCREW to achive no less than 600rpm at idle.
With a timing light it makes it easier to change the timing in smaller increments. I recemend to start at 7* then move up to no more than 14*, it's critical that everything works. All engines can rev with bad timing at tidle without pinging, it's only pings when it's
under load, and SCV sees more vacum when there is LESS manifold vacum. you're really close with 17 you want 19.5 to 20 on completely stock engine.
Just make sure the vacum lines are SCV to Distributor, and the can is good, IF you ping back off the timing 1* til it stops pinging, try going up a hill to see if it will ping.
Hope this helps, Good Luck!!!
Richard