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Old Nov 8, 2011 | 03:02 PM
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I saw a fella selling a '73 on this forum (thread closed). It was advertised that it had a "M40" - What is an M40?

I'm thinking a TH400 and a miss-print?
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Old Nov 8, 2011 | 03:04 PM
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Originally Posted by udornf4
I saw a fella selling a '73 on this forum (thread closed). It was advertised that it had a "M40" - What is an M40?

I'm thinking a TH400 and a miss-print?
M40 is the option code for the auto trans.
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Old Nov 8, 2011 | 04:24 PM
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OK.

I didn't know M40 = Auto

One would think, maybe A40 would be for the Auto - but GM has their own way of codes...

thanks!
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Old Nov 8, 2011 | 04:43 PM
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Originally Posted by udornf4
OK.

I didn't know M40 = Auto

One would think, maybe A40 would be for the Auto - but GM has their own way of codes...

thanks!
RPO codes. M is used for transmissions. L is used for engines, and so on. you should pick your self up the Corvette Black Book by Mike Antonick
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Old Nov 8, 2011 | 04:50 PM
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Originally Posted by Nowhere Man
RPO codes. M is used for transmissions. L is used for engines, and so on. you should pick your self up the Corvette Black Book by Mike Antonick
the most handy of pocket sized reference materials. since you probably don't want info on the newest of corvettes, you can usually find a used one on amazon or ebay for around $10.00. even if y ou want the latest and greatest version with the 2011 (or 2012) information it is under $20
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Old Nov 9, 2011 | 10:12 AM
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M40 was the option code for the TH400 the years it was available.

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Old Nov 9, 2011 | 03:52 PM
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Originally Posted by Easy Mike
M40 was the option code for the TH400 the years it was available.

And M38 was the usual code for the TH350, across divisions.

GM had traditional letter prefixes for certain categories of equipment; here are a few according to my failing memory:

A= Interior
C= Climate Control (C60= A/C)
G= Axle
L= Engine (L36)
M= Transmission (M22)
P= Wheelcovers (PO1)
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