MSO documentation

[PhilS]

I'm trying to figure out the meaning of the horsepower (SAE) rating found on MSOs. My theory is that the rating is max built to spec per cylinder. I noticed on the Daytona Yellow COPO Chevelle at B-J the number was 55. On a Camaro bought by a friend the number is 53.6. This car is supposedly a 375 hp car. I think Zs are 48. Kurt and Daniel have been trying to help but Kurt says an SS350 is something like 51 which might blow the theory. Charley thinks someone has already figured this out but doesn't remember who. I would like to see more MSOs to get a better understanding. The number on a new Vette is around 51. I think a Viper is in the same range. If anyone has an MSO for a 67-69 Camaro I'd appreciate your info or thoughts.

Thanks

[bilede]

53.6 is a 396 but wouldn't tell you which of the 3 versions of that motor it would of been originally.. 325hp, 350hp, or 375hp or even L89 aluminum headed engine.. tach or other clues maybe.. keep looking.

[Chevy454]

We talking about the "taxable hp" rating? Seems like we dug into this many moons ago on this...

[COPO]

We did talk about this several years ago on this board. It is one method to help determine what displacement engine came originally in a car. I have seen a number of discrepancies with solely relying on this method. I found quite a few examples of highly documented BB's with a taxable HP listed as a small block. I think the old thread talked about the formula for this calculation. It is displacement only.

[Chevy454]

Here is the formula...

Diameter squared times number of cylinders divided by 2.5

[PhilS]

Thanks for the help guys but I'm curious about this formula. More than one displacement can have the same bore so I'm not sure how it works. Does the SAE number apply to more than one engine size? Also when I ran through the numbers I wasn't getting a match to the MSOs I've seen. I'm assuming that the number actually has relevance but maybe not.