Swing Arm Swap for KZ750B1

I have a 76 KZ750B1, and I am looking to stretch the rear end a bit, the bike is just a touch too compact in length, and straight up and down shocks annoy me. Likely as it reminds me of dirt bikes. The bike is a little tall for my inseam too, so I have seen projects where longer swing arms tend to lower the bike with very liitle major changes to the frame.

I was at a local salvage yard, custom shop, and we were looking at a 78 KZ1000 that they have modded with a stretched rake, Harley tanks, Harley Bob Tail and a custom exhaust. I was telling the guys that the swing arm on the 750 is CONSIDERABLY shorter. We measured the two, and the one onthe KZ1000 is roughly 3.5 inches longer. Just the length I was looking for.

Will this swing arm swap onto a B1 frame? I know the 4 cylinders 750 has a smaller axle the the twins for some reason. Does the KZ1000 use the thicker axle too?
I guess what I am getting at is if I am going to go with a swing arm swap to get my extra 3 to 4 inches, what is the best way to go about it? I have read some of the other threads in using GSXR aluminum arms, and this is interesting, but I like the rounded steel onthe B1 as it matches the "older" rounded look I want. I will consider it of course, but am asking for some advice. I am getting used to the search function, so any help would be highly appreciated.

Thanks

Krakum1967