When I put these 35's on my '78 with 3.?? gears the speedo was expectedly way off. When I put 4.10's on there the speedo was just about spot on. I'm now putting the 4.10 axles with the 35's on my TBI'd '91. My question is, will I need to mess with my DRAC (been reading up on them) or will my ECU just see the 'normal' input because the gears are turning everything at a fairly normal rate??. I'm thinking of speedo accuracy, trans function and RWAL function. Has any one got this combo on a '89 to '91 with 700r4 and 241? Did you have to mess about with DRAC? Thanks, Mark.