GM cubic inch limitations

[SS427]

I am in desperate need of some facts if anyone could help and printed ones would be even better.

The question was asked of me regarding the reasons behind Chevrolet not installing the 454 in Camaros and Novas from 1970 on. My understanding has always been that GM limited the cubic inch vs weight in the Camaros and Novas due to insurance issues and possibly sales infringements into the Chevelles and Impalas. Can anyone help with printed material or at least honest quotes from GM? I appreciate your help in advance.
Rick

[king_midas]

I've heard it was because of a couple of reasons, some mechanical, and some reputational.

Mechanically, because of the use of the corp. 10-bolt axle as a perceived weak-link.

Reputationally, because performance was increasingly becoming an albatross around the neck, and the mfgr's knew the writing was on the wall regarding big engines, fuel, mpg, etc... In other words, there was no good reason to continue the engineering and federalizing of those engines into those cars, so they didn't do it.

[ORIGLS6]

The 12 bolt rear axle had been in place in both product lines for years.

[Late BrakeU2]

I know prior to 1970 GM had a restriction stating no mid size car engine could have a displacement larger than 400 c.i.(hello COPO)but that was dropped the following year.A marketing standpoint and insurance are the only plausible reasons-Camaros and Novas were entry level where as the Impala,Chevelle,Monte,(Firebird,GTO,Buicks) targeted the "older" buying influence who were much less affected by insurance due to age.On a side note I think that's why so many more of the latter have more docs-the people that bought them were generally older and knew the importance of keeping records jmo

[Keith Tedford]

GM had plans for the 454 in the Camaro. The parts books were printed up for it. Insurance was one of the big reasons I would think. No insurance. No car. Pretty basic. People who could afford a Corvette could also afford the 454 and the insurance. If people wanted a 454 and couldn't get it in a Camaro, they would buy a Chevelle. I believe the Chevelle was cheaper to insure back then as well. GM would already know that this was the last year for the hipo cars so that may have had something to do with the call as well.