Its very possible you hooked up the fuel lines backwards and blew out the regulator. When you reverse the lines, the FPR cannot regulate pressure and you are then at the mercy of the fuel pumps dead head pressure which can reach up to 110-120 PSI. If the FPR diaphragm is weak, guess who wins.
I reversed the lines, I got very lucky and the regulator held, when I loosened the hose clamp the line blew off and sprayed accumulated fuel all over. The regulator made a very loud 'pop'. I should have been more careful. Luckily the regulator survived and I switched the lines correctly and the car started and all is good.
In your case It's pretty obvious the regulator popped and you are forcing pressurized fuel through the regulator vacuum hose into the intake manifold.
Be aware I am not saying your fuel lines are backwards, they very well could be though. You need to make sure at this point.
You got some bad luck dude, my sympathies. But your only a FPR away from getting it running again. Hopefully this will be the last of your difficulties.
Best Wishes.