My '68 when I got it ran, but poorly. Similar to yours, weak on power, ran hot. It had been in storage when the original family brought it back to life. Work looked like it had been done at a shop that was previously the Chrysler dealer in town. I agree with not a lot of people are familiar enough with these cars anymore.
Carb was replaced with a reman unit. It was awful. Float wasn't even close to being adjusted. Check it/ teak it down even if someone says its rebuilt. Biggest single improvement. Mine went from afraid to pull out into traffic, to reasonable.
Went through distributor. Weights were stuck, advance can not operating.
Heat riser stuck.
Not saying I wouldn't make upgrades, but get what you have to a reasonable running point. IF you can't get what you have to work properly, how do you expect to throw parts at work and for those to work properly.
