Classic/Antique Car Repair: What Brand Oil and Grade ?, Mustang engine oil recommendations

Question
Hi Robert

I got a rebuilt 1966 Mustang Convert.With a 289 bored-out
30 thousanths.

I'm coming up to changing my oil. I just don't remember with
grade of brand my restorer put in.

I don't think at 5,000 miles on the car I should your Amsoil
sythentic (might leak thru the seal?)

You tell me Robert please what would you do ?
I live in the Las Vegas area; where it gets BOILING in the summertime, if that helps you.

Thank You Robert
GOD BLESS YOU
Ray : )

Answer
Hello Ray,

If you're engine was properly rebuilt, using a synthetic like Amsoil or Mobil One should be fine. Synthetics have a higher film strength than regular oil and will do a great  job protecting your engine in Vegas. That being said, even today's conventional oils are so far ahead of what was available in 1966, that you're safe using conventional or even a conventional/synthetic blend. Although I prefer Mobil One, most important is keeping the oil and filter changes at least once per season or more frequently depending upon how often and how far you drive.

Another option would be to use Shell Rotella. Formulated for Diesel engines, it  also contains an additive package that most closely approximates the needs of older engines.  

Again, in a new engine like that, going with a 10W30, also the original weight, should be just fine.

Good luck with your Classic Mustang