Give HemiDog a cigar. I believe that I welded studs in the tube.
I got all of the dollies at HF.
LISTEN UP!!!! Do NOT use the pnuematic tires on the rear of your car! I did and you see what happened. I ended up swapping over to the hard rubber tires. There are probably pnuematic tires that you can get that will hold that much weight, but the ones at HF are rated at 300# a piece. Not nearly enough for the rear.
Now, for you guys who still have suspension pieces under the car with tires on them, there are plate dollies that you can also get at HF that go under the tires and allow you to roll the car side to side and so forth. I used those when the car was still together.