Suspension

Sub-frame
RWD
1985-1989
1990 GM # 15656164 (10mm idler arm attaching bolts)
1990-1991 GM # 15644640 (12mm idler arm attaching bolts)
1992-1995 GM # 15674641
1996-2005 GM # 15248416

AWD
1990-1995
1996-2005 GM # 15009053

Control Arms
RWD
Lower Left
1985-1989 GM Part # 15634885 (No interchange. No aftermarket 2021-02-07.)
1990-1991
1992-2005 GM Part # 15969293 (No interchange.)
Lower Right
1985-1989 GM Part # 15634886 (No interchange. No aftermarket 2021-02-07.)
1990-1991
1992-2005 GM Part # 15969294 (No interchange.)
Upper Left
1985-2005 GM Part # 12474031 (No interchange.)
Upper Right
1985-2005 GM Part # 12524201 (Used on 1987-1992 Cadillac Brougham, 1993-1996 Cadillac Fleetwood, and 1991-1996 B Platform cars.)

AWD
Lower Left
1990-1991 GM Part # 15992479 (1992-1995 GM full size 4x4 trucks)
1992-2005 GM Part # 15020097 (No interchange)
Lower Right
1990-1991 GM Part # 15992480 (1988-1995 GM full size 4x4 trucks)
1992-2005 GM Part # 15020098 (No interchange)
Upper Left
1990-2005 GM Part # 12376163 (1992-1996 GM full size 4x4 trucks)
Upper Right
1990-1991 GM Part # 12388432 (1992-2000 GM full size 4x4 trucks)
1992-2005 GM Part # 12376164 (No interchange.)

Lower Control Arm Bushing Bolts
Front: m16x2.0x114mm grade 10.9 (110mm or 120mm regular stock bolts)
Rear: m16x2.0x137mm grade 10.9 cone point

Steering Knuckle
RWD
1985-2002 Left GM Part # 18060688 / Right GM Part #18060687
2003-2005
AWD
1990-1991
1992
1993-1996
1997-2002
2003-2005

2" Shackle - Shackle Raise 2" 3.50" Wide Monoleaf

http://www.airbagit.com/SearchResults.asp?Search=sha-as8400b

I don't think they are specifically designed for the Astro, but they work. To not bend them, I used a M14x2.0 120mm bolt with two washers per side between the leaf and shackle. The bolts are available from Chevy, have to ask for the lower shackle bolts for a Suburban/Tahoe. My dealer quoted under $6 each.

Rear shocks

RS5147 LS74 LS74 14.610 23.070 8.460 None - Stock

RS5315 LS74 LS74 14.840 24.050 9.210 None - Longer

Front shocks

RS5150 LS77 LS39 11.520 16.670 5.150 None - Stock AWD

RS5152 LS77 LS39 11.550 16.090 4.540 None - Shorter AWD

RS5244 LS77 LS39 13.530 21.750 8.220 None - Longer AWD