I used this for 2 seasons, about 8000 miles. It is a 6.200" (they call it a 7" balancer for some reason) neutral balance unit for 350s and any other internally balanced motors. You can use it on a 383 or 400 if it is set up for internal balance.
It's SFI approved and a lot stronger than stock. I had two stock 8 inchers crack and one fell right off the crank. These are rather expensive new. I paid $225 for this one. It's worth the money to know that won't happen again. It's also a lot lighter than any 8 inch balancer.
It looks brand new as you can see from the pictures.
Those marks near the center bore are supposed to be there. I did not do that myself. They give a little bit more of a press fit to make sure it stays put.
$150 plus shipping. I also have a billet timing pointer for this. $20
It's SFI approved and a lot stronger than stock. I had two stock 8 inchers crack and one fell right off the crank. These are rather expensive new. I paid $225 for this one. It's worth the money to know that won't happen again. It's also a lot lighter than any 8 inch balancer.
It looks brand new as you can see from the pictures.
Those marks near the center bore are supposed to be there. I did not do that myself. They give a little bit more of a press fit to make sure it stays put.
$150 plus shipping. I also have a billet timing pointer for this. $20
back up.
pm sent 
Sold-both for $175 shipped