1978 390 rear shock mount position

Hi, I'm in need of a bit of help. I bought a 1978 390OR in bits and the swing arm is not usable. I got another off Ebay but the shock mounts are further forward. The problem is that the one I got with the bike seems wrong as well as those mounts seem too far back. Would someone with this bike be able to measure the distance from the swing arm pivot to the centre of the shock mounts? This would be a great help and much appreciated, thanks

From pivot center-line to lower shock bolt center-line = 410mm

That's just what I needed, thank you