If you have NOT applied clear coat, you can use making tape to remove the decals w/o removing the paint. You may have to rub the masking tap in the area of the decal, but most of the time this will work
Admittedly, operating from memory, but the blue that was last applied looks much closer to how I remember the car from 1975. I'll be following with interest!
I probably saw this car race! I went to several USAC stock car shows, both dirt and pavement in the late 60's and early 70's. You did a great job with capturing the "feel" of that era in USAC stock car racing.