The original 215/60-14s were 24.16" diameter (Approx) and the 205/70-14s are 25.2".....
My speedo was always reading a little high- Getrag trans + stock-size 215/60-15 which are 25.16"- This is typical of how GM sets up speedos.....I converted my car to 16s with the rear tires at 225/55-16, which are 25.75" diameter- my speedo is now accurate.
The 195/70-14s are 24.75" diameter which would be exactly the same increase in diameter as mine.
Also, narrower tires will reduce steering effort at parking speeds.
[This message has been edited by cvxjet (edited 11-09-2023).]