I found a link the said look for the engine plate with the code. My engine has been replaced and I can not find a plate in the engine compartment. I see from the chart that for a 77 either the 4.11 or 4.88 was available. What was stock? I currently have 30 inch tires. I am think of changing to 32" or 33" tires to improve the highway ride. My mechanic said this is a better bang for the buck than spending $1500 to $2000 to regear the differential. In searching the archives I see some have used 33" tires without a lift kit using 9,5" widths, My rear qtr panels are cut high for bushwakers. Any advise on 32" vs. 33" tires w/o a lift are appreciated.