Only because I dont have a complete short block. I can go to 416 for roughly the same price is all. Without matching numbers, it really doesnt matter too much if the insides are bigger.
That guy I bought the VAT40 from had 2 340 short blocks he was selling.
Doubt he'll ship but I could probably get one on a pallet a bring to a fastenal.
Let me know if your interested - and I can PM you the links