What type of oil does a 77 take?

Is it 5W-30?

20W50...Castroil

Castrol GTX 20W-50 for engine and gearbox.

Thanks

Does anyone know what size oil tank a 77 has?

same as the others...I use about 4-5 quarts, i think

What oil you need depends on the part of the country you are in as well as the engine. You need a different oil in Alsaka than in Florida.

Best look on the castrol site. They have a lot of useful info.

He's in Colorado. 20-50 should be fine unless he lives at altitude in which case 10-40 would be a good winter viscosity.

Castrol 20W50, like everyone else! :)

About 3.7 US qts.