I have a 1968 olds Delmont 88 that needs a new gas tanks. I have found that i can order new fuel tanks for cutlasses of that same year. Does anyone know if that tank will fit me car before i purchase?

Thanks,

 

In a word. No. From the GM Oldsmobile Parts Catalog the listing for a 1968 Delmont Fuel Tank is Gp. 3.001, Pt. 405150. It fits:
67 - 69 exc. F85, 98 or Tor.
70 Delta exc. NA9 Opt.
The Fuel Tank for a 68 -69 F85 exc. S.W., V.C. is Gp. 3.001, Pt. 404078. Not the same.