You have a 7500 lb grawr for the rear.
About 4200-4500 for the front.
Total gvwr per GM 10,000 or 10,500 if it has a C7 HD payload pkg.
GCWR for a 454 rig and 4.10's is 16000 lbs. Frankly, from having an 89.....could not go up ANY hill over about 15% in grade fully loaded. TH400 tranny is a tall first gear trans, same as the later 4L80E, at 2.49-1, with TC around 4-1 overall low. Pretty tall 1st gear for a truck. I went thru the trannies every 30K like clockwork!
If you can find a muncie 4spe with 3.42 gears, you would be WAY better off frankly. That is equal low and tall gearing to a later model with an NV4500 and 4.10 gears. 3.73's would be ok too. Really do not need or want 4.10's with a direct drive tranny.
Marty
