frame id
 

ok i have a 72 gmc 4x4 the frame has been changed to something newer the guy i got it off of doesnt know what the frame is. where can i find the numbers for the frame and front and rear diff. and if i get the numbers can someone on here tell me what i have. im having a real hard time finding parts for it and im thinking of getting rid of it cause its a head ache unless i can figure out what i have. any info would be great

Re: frame id
 

Easiest way is the BOM number off the front axle (assuming it is a Dana 44). The number is stamped on the axle tube to the right of the differential when under the front of the truck looking back at it. It will likely take some scraping/sanding to see it. Look for a 6 digit number starting with a 6.