it does depend on the year. whether it is a one piece rear main seal or a two piece, if i remember correctly. I know my 79 is a two piece therefore the dipstick in under the master cylinder (drivers side). I think all one piece rear mains seals had dipstick on passenger side of engine.
SgtDel
aka "Andy"
www.delbridge.net
1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4