LMC Truck catalogue has me worried now... I have a D44 front and a 12-bolt posi rear end in my Blazer, and I found it has 3.08:1 gearing. Now, with 33" tires, this is all fine and dandy, I run at fairly low RPMs on the highway with my TH350, but eventually plan on swapping out my SM465. I also plan for a future 35" tire upgrade, so the 3.08 gearing will be somewhat lacking. I would like to go with 3.73s or 4.11s, but its my understanding from reading the catalogue that if I do that swap, I need to get a new rear differential case as well as the new ring and pinion set. Can anyone shine some light on this subject?