My buddy and I are building his 1972 Chev Blazer.  While under the truck I noticed the frame was cracked in a couple of places.  I have access to a frame out of 73-75 Blazer, will this fit?  I havn't pulled out the tape yet to measure, has anyone ever done this swap or heard of it?  

where are the cracks and how serious are the steering box is a givin Off-Road Design has a weld in frame brace just for the steering box mount other cracks i don't know if you have a welder and a cutting torch you can make your own braces (depending on your skill and if you don't trust yourself DON'T DO IT) if not just measure the frame to double check but it should match up.