you want something to weld in the frame to mount the shock mounts? why not just use some nuts and weld them in?
Ya the bungs are not always the best idea,they dont always stay in the frame rail,as I can say with my f100 shock mounts,going 80 heading to york pa my first year driving my 32,I hit a bad bump on a bridge and pulled all 4 welded bungs out of my frame rails,that welded nut idea sounds good.
The first set of weld-in inserts that were supplied by So-Cal for their F-1 shock setup pulled out of the frame the first weekend the customer had the car. Now we make an insert on the lathe that goes all the way throught the frame, welded on both ends and tapped for the retaining bolt. No more problems. Frank
Fab32is right, my So Cal bungs ripped out of my frame on my first cross country trip, do it like he said so it will hold up