dssur
+1y
I built a jig to go under the stock frame with pins that stuck up through the centers of the original body mounts. I cut these pins off flush with the tops of the body mounts. Now I knew excatly where and how tall all the body mounts were.
Next I braced the front clip to the jig, especially the core support on both sides. I diconnected all the fuel and brake lines from the frame rails, and the driveshaft, anything that ran to the rear, as well as unbolted the transmission crossmember (after supporting the tailshaft of the tranny to the floor) and cut the mounts for that crossmember off the frame. I set them aside.
Then I found a nice spot behind the front suspension on the framerails where it was mostly horizontal and just chopped off the old frame. I laid in the new rails using the jig as a reference, sliding them into the old frame about 5 inches and plug weldding and plating the joint. I cut the top of the stock frame down a bit so it would not interfere with the floor (It ended up hitting it just slightly so I had to modify the floor a bit.
I welded in the tranny crossmember mounts again, then welded in a center crossmember that had been notched for the exhaust. I welded up a carrier bearing crossmember as well, that held the carrier bearing.
Using 1/4" thick mounts, I first welded the original rubber mounts to them, then I held them to the frame letting those locating pins poke up through the exact centers 2 1/5 inches. I welded them solid and gusseted them.
I dropped the core support mounts the same amount and notched the core support for the lower rad hose. Some people like to cut the whole thing off and lower it, I think this needlessly complicates things by lowering the strut bars with it, which can be a problem if you run big wheels.
I built the rear frame clip and 4 link at this point, but you dont have to yet, you can just plop the body back on and bolt it down. If you lowered the tranny mountsl like I did, you dont have to cut the tranny tunnel, but you should lower the motor a bit to match. All of my body mounts lined up perfectly, I could see daylight right through them all. And when I laid it out and put a seat back in it, holy crap you really felt like you were on the freakin ground. Way different than a traditional bd.
Lots of pictures in my profile. Took about three months in an understanding friends shop (45 minutes away!) while I went to summer classes and did summer stuff with the family. I could probably do it again inside a week with that kind of time.