Temporarily disconnect the vacuum advance. Back the timing off from 27 until it does start OK when hot. Whatever number that is, probably around 18 degrees, is where your initial needs to go.
You probably have a stock distributor with way too much mechanical advance if it goes to 52 with the vac advance plugged.

Since your total timing still needs to be 34, that means you have to modify the distributor so its total advance is 34-18 or only 16 degrees.
I recommend one of these:

http://www.4secondsflat.com/Mopar%20Mechanical%20timing%20limiter%20plate.htm

Far easier than welding up and filing the slots.