I've rebuilt 3 or 4 Vikings. They're not easy to repair and are prone to some issues that need quite a bit of work and money to deal with. $40 is a fair price for a donor machine, but keep in mind that if it has a cracked cam stack or it hasn't been completely rebuilt in the last 10 years or the wax removed from the inside, it will need it. Most repair people won't deal with them a s the labor time involved is high. It would cost a lot of money and it's not a beginner machine. I have two that I use on occasion. I find them a bit noisy, rough to sew on and they're not great at FMQing. Honestly, they tend to be my least favorite machines in my 30-35 machine inventory.