No one has ever posted a documented GM paint code for green (or, yellow) USA 261 engines.
People have suggested these colors for green 261s:
Alpine "Detroit-Diesel" Green
John Deere Green
Plasti-Kote 225 Alpine Green
Dupli-Color Engine Enamel DE1618 Detroit Diesel Alpine Green
People have suggested these for yellow 261s:
12 oz. Farm Equipment John Deere Yellow Gloss Enamel Spray Paint
Daytona Yellow (from Cosmo)
"Edsel/Pacer" yellow (amtrakjoe)
VHT Yellow engine paint
Duplicolor Daytona Yellow engine paint
Rustoleum Daytona Yellow engine paint
Eastwood Yellow 650 degrees paint
