Finally, after much research, I found the 61 production data revised Feb. 61 including the AMA Specs and a special supplement for the SS option and 409. Just about all the factory data you could want.
http://www.gmheritagecenter.com/gm-heritage-archive/docs/Chevrolet/1961-Chevrolet.pdf
Other years are available also at the GM Heritage Center website:
http://www.gmheritagecenter.com/gm-heritage-archive/vehicle-information-kits.html
Ray,in 1971 GM went to the "net hp rating'system.The ls5 in 1970,with a 10 to one compression on the "gross rating'system they used in those and eariler engines was around 345hp.This was on a blue printed engine with no accesories installed and headers.Your 72 had 8.5 compression,exhaust manifolds,most likely a retarded timing chain set-[same cam as the 325hp 396],and "smog"tuning .There is most likely the difference in the hp numbers.
Just like the dissapointment I felt in 71 when the new Corvette I ordered was only rated at 270hp (350, 4 spd).:
Ray, I have a buddy here that has an original Monte SS 454 for sale minus engine. I can't remember the year exactly, but I think it's a 70.
Ray,in 1971 GM went to the "net hp rating'system.The ls5 in 1970,with a 10 to one compression on the "gross rating'system they used in those and eariler engines was around 345hp.This was on a blue printed engine with no accesories installed and headers.Your 72 had 8.5 compression,exhaust manifolds,most likely a retarded timing chain set-[same cam as the 325hp 396],and "smog"tuning .There is most likely the difference in the hp numbers.
TTT for the Tech section.
Finally, after much research, I found the 61 production data revised Feb. 61 including the AMA Specs and a special supplement for the SS option and 409. Just about all the factory data you could want.
http://www.gmheritagecenter.com/gm-heritage-archive/docs/Chevrolet/1961-Chevrolet.pdf
Other years are available also at the GM Heritage Center website:
http://www.gmheritagecenter.com/gm-heritage-archive/vehicle-information-kits.html