Chevrolet engine designations

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Does anyone know how GM decides on their RPO codes for engines? The reason i'm wondering is because i did some looking and it turns out the LT1 could come in a 260HP flavor with 2bolts and iron heads (impala SS/9C1), a 300HP or 275hp with 2bolts and aluminum heads(camaro), or as a 3xxHP or 275HP with 4bolts and aluminum heads (Vette), plus MANY other HP ratings and variations.

I also saw the new Z06 Corvette motor (348 CID/406HP) is designated as the LS6 as was the 450 HP 454 the put into some Chevelles in 1971. . .

Do they just pick random numbers and say "this is the order code", or is there some logic to it?


posted by  Hoxviii

I have done some reading on this and the best answer I can give you is to say the RPO numbers are organized chaos. The only thing that is a given is that the first digit will be a specific "grouping". For example "J" is brakes, "L" is engines, "M" is transmissions, "Z" is body/appearance/convenience packages. The next two seem to simply come in numercal order as they're developed or in some cases a designation is reused to play on the nostalgia factor.

Not much help but maybe a tidbit you didn't know.

posted by  vwhobo

Organized chaos, that's what i figured it was. I knew the leading character was what the number applied to adn then alsofigured the rusing of numbers came in with nostalgia and bragging rights. Think of what happened when the chevy guys first heard the Z06 was getting an LS6, their minds went straight to a big block dumping more power to the ground than anyone could ever use (well, not quite on the too uch power part, but you get the idea :wink2: )


posted by  Hoxviii

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