This is such a ridiculous debate. If you do your homework and match everything about each engine like heads, compression ratio, carburetor, intake, exhaust, and camshaft specs, you will find that both engines make only marginally different numbers in the end. So, to debate which is better, an olds 350 vs. a chevy 350, is pointless due to the fact that given equality in every other aspect other than make and bore/stroke, they will make almost equal power.
Whether it is right or wrong to put a chevy in an olds or an olds in a chevy is different. There is no right or wrong. Given that each engine performs essentially the same as the other, the matter is as simple as picking what color to paint your car. It comes down to the owner to decide. Regardless of the manufacturer of the car, the owner of the car has sole say in what will be done to the car. Saying you 'can't' or 'shouldn't' put a chevy in an olds or vice versa is wrong. There is no can or can't. It is, in the end, up to the owner to decide and up to everyone else to respect their decision.
Whether it is right or wrong to put a chevy in an olds or an olds in a chevy is different. There is no right or wrong. Given that each engine performs essentially the same as the other, the matter is as simple as picking what color to paint your car. It comes down to the owner to decide. Regardless of the manufacturer of the car, the owner of the car has sole say in what will be done to the car. Saying you 'can't' or 'shouldn't' put a chevy in an olds or vice versa is wrong. There is no can or can't. It is, in the end, up to the owner to decide and up to everyone else to respect their decision.