Welcome Julie.
I googled this. You are confusing our "Grumpy" with Bill Grumpy Jenkins.
Lots of youtube videos came up.
But please stay and have a look around. Lots of good information here.
To answer your question: He eventually hooked up with Dave Strickler in the early 1960s to campaign the series of “Old Reliable” Chevrolets – including the very first 1963 Impala Z11 lightweight car – before switching to Dodge in 1964.
I would think he got the car directly from Chevrolet. https://www.hemmings.com/blog/2012/03/29/drag-racing-legend-bill-grumpy-jenkins-dies/