Plymouth Duster of 73

So if you needed to rebuild the engine to a larger bore , the law does not restrict this. And if the block and or the head were shaved to increase the compression (and the power), I would bet that would be OK as the law could not tell from looking at the outside of the motor.

I decked my block 90 thou and shaved the head 10 giving me an estimated 10 to 1 compression ratio with an estimated horsepower of near 200 - of course the new cam, 4 barrel carb an headers all contributed to that. Looking at my motor it is a stock looking 65 225 with add-in’s - the headers and carb/intake.