1977 KZdisc brake spoke rims on 1981KZ??? Cafe Project

Hello,
First time to post here, so I applogize for not introducing my self first. I have a 1982 KZ1000 J LTD that I bought several years ago from the original owner with 12,000 miles on it. I started working on it, kids came along and the project stalled. Anyway I found a guy that started building a drag bike back when, and his project stalled.... sounds familiar. Anyway he has what look to be 1977 or so KZ1000 wire wheel hubs laced to Sun rims, 1.85X18" front, and 4.25X18 rear. The rims look almost new, and he has some sort of LONG swingarm and a very butchered frame. He wants $550 for all of it, or the same for the rims and swingarm (the rest is junk).
Will the front rim be a drop in fit for the 77 disc front rim? The rear rim will take a 150-160X18 tire, don't think that I have clearance on the stock swingarm, but other than that will this rim drop in fit the rear of my bike? The swingarm he has is 30" overall length, may be able to cut it down, but not sure if I can get back to stock wheelbase, which is near where I want to be.