So I have a 1980, K10 rcsb Silverado, TH350 with lockup, 205 transfer case. Glovebox says it's an "HD" transmission, what will my transfer case input shaft splines be? I wanting to convert to a 6L80e transmission.
In the post it isn't clear but looks to be 27 spline:
"27 spline (from Turbo 350 applications): (1971-79) The units supplied with a T350 automatic have a 27 spline male input shaft.
32 spline SHORT (appx 2" stickout)
32 spl LONG a(appx 3-5/8" stickout)
These are both from (Turbo 400 applications) (also some SM465 86-up may have used a 32 spl input.) We have seen both a short (about 2.0" stickout) and long (3-5/8"" stickout) versions of this gear. The adapter casting in both cases is 4-3/8" long. With the short input, the trans will have an output shaft that sticks out of the main case of the trans appx 4" With the Long input, the trans will have a shorter mainshaft: Sticks out of the main case about 2.5"
1979 to 1985 GM NP205: 8 bolt "racetrack" bolt pattern:
During these years, the GM NP205 showed up behind Turbo 400 and SM465 Transmissions in 1 Ton trucks only.. 1/2 and 3/4 T trucks began to be supplied with the NP208 instead. SM465 units will still typically use the 10 spline input. Turbo 400 units have the stout 32 spline female input (in most cases the short 32 spl input, about 1.5-2.0" stickout) however still uses the 8 bolt "racetrack" bolt pattern."
