1/8 good to use.

No way. 1/8" is only .125" thick. No way in hell would I use that for bumper brackets.
The 2 org brackets that mount bumper,to body ,I am useig now,do you s
No, they are twice that at the frame. I just installed the front and they are at least 3/8" thick where they bolt to the bumper, probably thicker and they are heavy!
Thats what i am useing now,org bumper to body brackets there are 2 holes to mount 70-72 mount at valance,74 only 1 hole to mount,thusssssss i have to make up the last hole hence the bracket i have fabe up to mount to the frame.