This diagram should work.
http://ww2.justanswer.com/uploads/ZZdaryl/2011-02-05_223731_belt.png
You can look up the belt on www.rockauto.com
GOODYEAR Part # 4060940
GATES Part # K060721
DAYCO Part # 5060937
Take your choice.
_________________
98 Riviera SC3800 All stock except gutted air box.
1970 Buick GS455 Stage1, TSP built 470BBB, 602HP/589TQ
Best MPH, 116.06 MPH, Best ET, 11.54
https://www.youtube.com/watch?v=UHCda-t_Jls
https://www.youtube.com/watch?v=sfT2tEO4XcU