Engine code for 68 Shelby

[Armymustang67]

I saw the gas monkey episode about the 68 Shelby GT500. The Marti report shows a 428 4V PI. But when entered on the mustang decoder it shows as a 390 4V. I know the R and Q are 428.

Did I miss something? Asking experts for help and to clear up confusion.

Thank You

Lewis
US Army Retired 21 years

[Coralsnake]

Shelby codes are different than Mustang codes.

S = 428 PI

[Coralsnake]

Peter
US Air Force Retired 28 years