The chain you see in the photo is a shortened GM chain, the same way GM did it for the racers.
In their customer kits they supplied a new, correct length chain from their supplier.
I took the GM chain and just used a chain splitting tool to shorten it. It's just like a motorbike or bike chain - remove links and then re-insert the removed pin and peen it over to re-form the rivet. You can read this on any mountain bike or motorbike site about chains.
The standard balancer GM chain is (from memory) 75 links and it needs to be 52 for this modification, so you count the links, split the chain at two points, leaving 52 links and then close the chain back up.
You can grind a pin (carefully) and just throw it away, but you'll need to press the other pin out because you'll need it again.
I've seen your work and you'd do this easily.
You can buy chains made to length (an example https://www.bearings...s/roller-chain/
)- there is nothing special or sophisticated about the GM chain.
I have not made any measurements as it was more pleasing to buy the splitter kit and keep the tool. I'd anticipate anyone else doing this modification would buy a kit too.
I have a new SAAB kit here so i'll be making a new short chain from the new balancer chain. You are welcome to the short chain in the picture if it will help you.
Edited by blackoctagon, 17 February 2021 - 11:04 PM.