[77Impala]

http://www.alldatadiy.com/about_alldata/index.html
Repair, TSB's, Recalls plus more (1982-current)

http://www.eautorepair.net/
Mitchel on Demand for single use account (1982-current)

http://www.haynes.com/
Repair Manuals (1969-2005)

http://www.chiltondiy.com/
Repair Manuals online subscription (1968-2005)

http://www.capriceclassic.com/spids.html
Here is a webpage to decode the RPO codes on the trunk lid SPID. (Mostly 94-96)

http://www.compnine.com/vid.php
Comprehensive GM VIN Decoder

http://cadillacfaq.com/rpo/index.php
GM RPO Lookup.

http://www.nastyz28.com/decode.php
Vin, Engine, Trim, plus more decoders. Covers 67 - 84

http://www.mortec.com/
Chevy Block Numbers, Performance Enhancements, Engine and Holly Carburetor Information (1958 - current)

http://www.donsautopages.co.nz/
Chevy Head Numbers, Performance Enhancements, Information (1958-1996)

http://www.impalaclub.com/naisso/ss_handbook.pdf
Resource infomation for the 94-96 Impala SS (Should work for all LT1's) written by Qalo's SS