finding factory spec's for 69-72 blazer

[wytnuklryd]

I have been browsing this forum for quite a while and did not feel the need to post until now. I have a project 1969 K-Blazer and I am converting it to a 2WD and have had a hard time finding spec's on wheelbase for these model's. I have a 73-87 IFS assembly that seems to line up well on the factory frame rails.(in fact I'm using a factory hole as a guide and it seems to place the center of the rotor where it should be in stock form)
My measure twice cut once mentality has come in though, and I don't want to weld up the crosmember assembly until I'm absolutey certain it is in the correct location. I've heard that this is a common swap done to these vehicle's because of the rarity of the 2WD in these original Blazer's. I also know that a 2WD assembly from a 67-72 1/2 ton would have been a much easier swap as it truly uses the same rails for both 2wd and 4wd. I just chose to use the 73-87 1/2 ton unit for it's factory 5 lug disc brake rotor's and the availability of part's for years to come. (factory and aftermarket) Also the rear leafs will be swapped for a coil over four link set-up. I live in sunny AZ and have intentions of cruising the truck with the top off 90+% of the time. Any reference link's or personal experiance's would be greatly appreciated. Thank's in advance.