CY & CX 400THM: differences & similarities

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For 1969,is that a correct statement?..wasn't the CX early for all those Spcl.Hi-Perf equipped cars,later superceded by the CY for all those Spcl.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

[61 vert]

457 date would be around april 3rd which would put it slightly before the April 14th date mentioned as a possible cutoff date.I have a CY dated 478 ,2 weeks after the April 14 date. If we could come up with a bunch of CY and CX dates, a cuttoff could be narrowed in on.As far as comparing the trans cutoff date to when the cars switched, that would be tough.I suppose that they could have been intermingled until the CXs were all gone, or different plants could have run out of CXs at different times.Does this make sense?