Pro-Flo 4 stalling on cold starts and running rich

I’ve just had my 1973 Plymouth Scamp back from the shop, it’s powered by a modified 360 Magnum. It’s running a Pro-Flo 4, that’s been completely factory reset, as it’s had all sorts of fuel pressure problems. Now has new fuel regulator installed and TTI headers, so had to had ECU reset to self learn - only problem is now it starts lumpy, and as soon as I give it some throttle, not the full heavy right foot, it stalls when it’s cold - when engine is warm it starts straight up. Also, smells like it’s running rich. Any Pro-Flo 4 aficionados or users have anything to share - some say remap. I’m away this week, but scratching my head getting ready to play with her and sort her out next weekend. What do we think it could be? Not had this before!