proper fuel

[glenn brady]

I own a 72 Eldo with 97K miles. 500 V8. What is the proper fuel to run in it ? The prior owner told me 1 tank hight test, then 1 tank normal (87) octane.

Someone else told me I needed to add a leaded addititve.

[denise 20352]

  87 octane unleaded is fine.  In the summer, with the air conditioner on, you might want to use 89.  Any more octane is just a waste of money.

-d

[Rusty Shepherd CLC 6397]

Also, you will definitely not need a lead additive.  All 1971 and later GM engines were designed for unleaded gasoline.