Building a VB with a mild (around 320hp) with a V8 T5. Have a disk 10 bolt but has 2.60 gears (out of car in do nic). tyres are 245/45/17. How bad will it be with a 2.60. Its a cruiser on the highway, not a traffic light dragger. I know I can change to 2.78 but if I want 3.08 or higher I have to change the carrier etc. Will it labour with such a set up (a dog to drive) and should I cut my loses and do something elese with the diff?
Some good points posted already, especially the
"change it".
A 2.60 snail, 2.78 turtle, 3.08 would be more suited all round considering 4spd plus o/d box, especially as highway cruiser with 5th for fuel economy. Most diff ratio’s are chosen basically on 1st n last gear you’re running in car g/box apart from other drivetrain/engine sheet. Lower ratio diffs use /have higher 1st gear ratio boxes and no o/d.
I had before conversion 6cyl, 8bolt 2.78 with 3spd traumatic auto, also used for standard 253 engine.
Now running 304 with 700 4spd auto and I have VK Salisbury 10bolt 3.55 LSD and its brilliant in city traffic without o/drive and great with pick up as highway cruiser with overdrive.
Uses slightly more fuel due to higher revs/ratio but still economical and factory feel if you don’t plant the old lead foot.
I originally wanted to use 3.36 slight improvement in pickup and acceleration all round to a common 3.08 BUT couldn't find one, I was lucky to find the rarer 3.55 10bolt lsd and happier I did in the end apart from knowing, eventually to many spins and the lsd spider gears will croak.
Since your building engine, Look for a standard VB/VK 3.08/3.36/3.55 10bolt LSD Salsbury as your best option depending on what you find.
If you decide to change to the VK on B/W 28 spline diff is worth the spend for a V8. B/W 25 spline is a bit weak for V8 even if you drive like a grandpa.