1969 was the last year for 6 lug on chevy 1/2 ton trucks. 1970 Chevy trucks starting using 5 lug.
As for the IFS swap, I am doing one of these right now. Just took out the entire crossmember with spindles, discs, etc that was attached to the crossmember on a 1973-80 Chevy Suburban.
It is Sooooooooooo Easy! Yeah drill out a few holes a litttle bigger and two new hole will need to be drilled and your set. I also got the power steering box and pump too.
Why buy all that after market junk at those high prices when it is sooooo easy to do it yourself and save!
The power steering box will set the same distance from the frame as the original box, so the steering rod will line right up. You will need to take off the steering joint and use the newer style which bolts in. So, all you need are spacers and then drill some new holes in the frame.
Once you get the system it is pretty obvious what needs to be done. And since you are going to put disc on the front and drum on the back you will need the proportioning valve too.
Might as well grab the power booster and do that too.
My 1966 Suburban will drive like a new truck when I am done.
