Firing issue

I hope you adjusted the mechanical advance inside the distributor?

If you had 50* total on it without vacuum, then you were on your way to hurting the engine.

Having to mat the pedal when starting is also indicative of not enough initial timing.

Put a timing light on it at idle and see where it is set. Sounds like they did the total timing deal which may well be the correct total number. It should have 16-22 is my guess, but they backed out 12ish degrees. you need to get both ends of that under control.

My guess is the 38* is total timing. I took it for another drive and it runs so smooth.

The timing was initially set by my brother and we were doubting his very old timing gun.. We tried timing the car two different times and the numbers where different each time. So we just set it by ear until it smoothed out. Thats how the 50* came up. It ran well enough to get it home.