The Plymouth Weslake DOHC Motor from the 60's
Back to the 1969 Plymouth Indy car effort....
It was more than just Indianapolis 500.
And STP had a
SEVEN Indy 500 entries that year. IIRC, they brought
5 plus completely different chassis. Mario won in a completely different back up car than he crashed in practice.
The Plymouth engined car did not qualify for the Indy 500. The other STP cars were Ford and Offy powered.
STP also ran sprint cars. Dirt track were part of the USAC annual championship.
1969 USAC Championship Car season - Wikipedia
Greg Weld put a Plymouth powered sprint car on the pole twice in 1969. STP teammate Mario Andretti ran an Offy powered sprint.
... a complete different time in racing than today.
Here’s parts of 1969 STP Calendar