CY & CX 400THM: differences & similarities

[hiperf69]

Just a couple of questions that have come up.
Would anyone have any info as to why GM put "CY" trans in the Impala's and Chevelle's
And the "CX" trans in the Camaro's and Nova's?
According to the chart on the first page of this thread the diff. between "CY" and "CX" are the case, and the "CX" case is the same as the Std case,and the valvebody.
Am I correct in assuming the valvebody to be different because of the weight of the Impala,and Chevelle being more than the Camaro's and Nova's
One more thing, did the Corvette's use the "CY"s also?
Thanks,Joe.

[Mr70]

"Would anyone have any info as to why GM put "CY" trans in the Impala's and Chevelle's
And the "CX" trans in the Camaro's and Nova's?"

For 1969,is that a correct statement?..wasn't the CX early for all those Spcl.Hi-Perf equipped cars,later superceded by the CY for all those Spcl. Hi-Perf equipped cars?

I think there was a valvebody difference,but I'm not sure if that was it.
Thought the 427/430HP & 435Hp Corvettes did come with the CY,as of April 69.

[hiperf69]

Sorry, Yes this would be for '69.This what I am trying to find out,was there a change mid- prodution or were they both used all the way through from start of 1968.If there was a change,do you know what date this happened,Thanks.Joe.

[Smokey]

Wasn't the CY also the police car version too?

[Mr70]

Here's some docs..









427 COPO Camaros & Novas show L-78 on their buildsheets as that's how they were assembled,and then had a 427cid. installed instead.I would think the CY trans was available in all 5 vehicle types w/Spcl. Hi-Perf 427cid. as of 4/69.

[hiperf69]

Thanks Rick ,this if I read this right,would mean cars built after this date April 14 1969 would have received the "CY" code trans. Books are good!!Joe

[Mr70]

Paper reports usually came out after the act was actually being done,so I would say even a lil before April 14,1969.
They may have been installing them much earlier then that,but because my books of these are incomplete,I don't have any earlier dates on paper to share then this one..

[deuce-less]

my 69 07D built L-78 nova came from the factory with a CX coded trans