I am new here and hope you can help me out.I will be byeing a k5 after I sell my cj and have couple of ?s . What year did GM start puting emision control on k5s. My sub. is a 78 and has none is it the same for blazers? Did they just have a cat at first or did they go all out with emisions from the start? Also what was the last year of the full removeble top?Any thing else blazer specific to look for? Thanks in advance for your help.