Follow Milliagan’s recommendations above this will provide yourself with more information to diagnose the problem.You don‘t have to have a PCV. A lot of guys just run filters on those. I wouldn’t think that is your issue.
I know the PO tinkered with a lot of stuff so I wouldn’t check those things off the list. There are plenty of new parts that I’ve put on that take a lot of work to get running properly. Unfortunately with all the things that have been touched you really have to run down the entire system from fuel tank line to pump to filters to carb to timing to vacuum lines and such. Make a big list and just start checking stuff off.
What’s your vacuum pressure at idle (check when warm) and is it steady?
What is your cold idle?
What is your hot idle?
What is your initial timing?
When does your timing advance come on and how much advance does it give?
Does your choke close properly and then how long does it take to electronically open?
Check fuel pressure in the lines, should be 4-7psi.
Float set properly? Open it up and make sure there isn’t debris in there (If he replaced all the lines, typically you want to purge the lines with a gallon or so before hooking it to the carb.)
I’m betting one of those gets you on the right track.