Classic/Antique Car Repair: 1966 Mustang Shelby Gt350, detergent action, mustang shelby

Question
Hey dick, I just purchased a 1966 mustang shelby GT350. Its an “A” code
289cu HI-PO 225hp V8, I changed it to a c-4  auto transmission. I was
wondering what type of oil I should put in it and if there is anything I should
know about this car. I am a mustang lover but I want to make sure that I keep
very good care of this beauty. Is there anything in mind for tips or anything
like that which I should keep in mind?

Answer
For the engine, I prefer Chevron RPM-Delo 400 15W40 Diesel rated oil, unless the engine has just been rebuilt and not yet broken in. If that is the case, use a racing oil from Valvoline or Castrol with ZDDP additive to assist in breaking in the new camshaft and lifters - use that for at least 5000 miles, then you can switch to the Chevron, which has better detergent action, in my experience.  Change the oil filter with every oil change, and use a good oil filter- I prefer those made by WIX, which you can buy at NAPA stores if you specify their premium brand.

For the transmission, you'll have to find an owner's manual for a car that came with the same transmission as you have and see whether or not type F transmission fluid is recommended.  If not, then use Dexron-Mercon III.

For the cooling system, be sure to take good care of it, by changing the coolant every 2 years and using a good brand like Prestone anti-freeze, in at least a 30% concentration.

That's about it - just keep the shiny side up!

Dick