I currently have a 741 case, clutch type, that HAD 3.91 gears, before the pinion and ring gear were destroyed at the track last weekend. I am now finding out that 3.91 gears sets aren't readily available (new) for my case. So, now what do I do? Should I try to find another 3.91 gear set....replace the 3.91 with 3.73 or 3.55.....or just buy another center 489 or 742? I have a 489 SG with 3.91 gears, that I can borrow until I figure something out. Is the 741 worth the time and effort? It's mainly a street car that sees 10-12 passes at the track a year.