how to have the car to install Sub frame connectors

[CudaChick1968]

wont the powder interfere with the welds?

It can ... to those who don't know what they're doing. :-D

 

[TrailBeast]

Update that gap at the rear is now only 1/4 of an inch. I cant get it any closer.

If you use a straight section for the connector you will have that gap.
I sliced the corners and bent that bottom peice up to the frame and welded it up, then ground the leftover corners down to match.