I would definitely remove the front differential to regear it.
What do you plan to do with your truck.....four wheeling, heavy towing, light towing or do you live in a hilly or mountainous area? Those factor in on what gears you go with.
If you go with 285 that are 33" tall, 4.11 gears will...
Hey, it was all I had and no one else works on my truck or vehicles. I also have two Buick Grand Nationals that I do not trust to anyone else either.
I would be more than happy to change it out if you would like to send me some.
My battery to starter cable was in good shape. I ran a piece of welding cable directly to the back of the alt and left the oem negative cable in place. I ran a piece of welding cable from the battery to the block and attached it to the passenger side where the mechanical fuel pumps used to...
Here is a great source for gears and differentials. Cheap and free shipping.
http://www.ronsmachiningservice.net/gm-8-5-8-6-2/
Summit is a little cheaper with the trutrac.
https://m.summitracing.com/parts/dtl-913a481/applications?prefilter=1
I have a 1997 Yukon with 180 miles. With 285's and 3.73 gears I get around 12.5-14 combined mileage. Thinking about swapping to 4.10's to help my around town mileage. I calculated that my rpms should be the same as with the factory tires and 3.73s.
A little tip that I found when replacing my intake gaskets was to cut 4 pieces of all thread about 1 1/2 - 2" long to screw into the 4 corner intake bolt holes to help guide the intake straight down without messing up the silicone or end gaskets when dropping the intake back on. I cut slots in...
I have a 97 Yukon with 33s and 3.73 gears and the engine kinda lugs at about 1600 rpm in OD at 60 mph. I get about 18 mpg on the hwy, 12.5 mpg average hwy/city.