?ctk engine code?

[robert leazenby]

My engine pad is stamped with engine code ctk but everywhere I read indicates codes of CTU or CTV (I know that CTV is for the famed ZR1). I am currently looking at the 1953 to 1982 GM Corvette parts and illistration book, which does not list CTK. I know the motor is original, any explanation would be appreciated.

[Mark Ring]

Re: ?ctk engine code?

Robert,
How do you know it is original? I have several listings for "CTK", but none you would want to know about. 72 307, 74 400 caprice commercial California, 78 305... What year is your car? How about a casting date code? Just trying to figure it out.
-Mark.

[Walt McGaw]

Re: ?ctk engine code?

Hello Robert,

I'm probably way off here (I only have limited information that goes from 1971 to 1978) but I could only find the CTK code for a 1974 400 cu in police edition engine. What year Corvette are you working with?

Walt

[robert leazenby]

more info

I am dealing wiht a 1970 LT-1. The car's vin is indeed also stamped on the pad. Engine casting is 3970010. The only thing I can find is that CTK is a late 70 code for the LT-1, but my chevy book does not list. My car was completed in early July, 1970 (last production month)

[Mark Anderson]

Re: ?ctk engine code?

Robert,
My '70-'72 NCRS Judging Manual shows CTK interchanging with CTU as the Broadcast Code for the 350/370hp (LT1) w/ 4 speed and transistor ignition.

Mark

[Mark Anderson]

Additional CTK Info

Further reading indicates that the CTK coded engines actually had a smaller oil pan than the CTU engines. This allowed clearance for power steering. The Judging Manual also indicates that the first recorded (LT1 survey) CTK engine was s/n 9021, built May 12, 1970.

Hope this is helpful!!

Mark

[robert leazenby]

Re: Additional CTK Info

well at least I am not crazy and that further confirms the original engine theory. Mine was built sometime around the end of June/beginning of July. How would I find out which day with a ser# of 13904.

[Mark Anderson]

Re: Additional CTK Info

Your trim plate (inside drivers door hinge pillar) will have a build date. The top line will have "CHEVROLET" then an alpha-numeric code next to it. The first value will be a letter signifying the month (in '70, A= Jan, B = Feb,....) and then two numbers which are the day of the month.

Mark

[robert leazenby]

Re: Additional CTK Info

my trim tag indicates June 30, 1970, but all information that I have showes my VIN being completed in July (Probably towards the beginning) with the final VIN of June being 13829 (mine being 13904) My tank sticker shows "Exp. date of production- 00/00/00

[Joe L.]

Re: Additional CTK Info

Robert and Mark-----

The date shown on the trim tag is the body build date. So, this date can precede the actual completion of the car and assignment of VIN by a day or two (much longer for AO Smith build mid-year bodies).

As I recall, the "CTU" suffix code was used for early 1970 LT-1s. These had "6 quart" oil pans. The "CTK" code was then used for later LT-1s which were equipped with "5 quart" oil pans. Power steering could not be installed on the "6 quart" pan LT-1s. Later 1970 LT-1s ("CTK"), whether they were power steering equipped or not, used the "5 quart" oil pans.

The "CTV" coded LT-1s for use with the ZR-1 performance package all used the "6 quart" oil pan. These engines also differed from the "CTU" and "CTK" LT-1 engines by virtue of the fact that they included bellhousing and 12-3/4" flywheel for use with the 10-1/2" clutch.

Keep in mind that the FUNCTIONAL purpose for engine suffix codes was to distinguish between the various engine configurations AS DELIVERED from the engine plants. In the vast majority of, if not all, cases, a different engine suffix code indicated some difference in the AS-DELIVERED engine. The difference between differently coded engines may have been minor, but there usually WAS a difference. GM didn't make a practice of assigning different suffix codes to identically configured engines just to confuse things for the assembly plant folks. In fact, the purpose of suffix codes, which are a form of a broadcast code, is to SIMPLIFY things for folks at the assembly plants.

[Robert C.]

Re: vin#/birthday book

I don't have one, but somebody could look up your vin in the Corvette Birthday Book for the correct date your car was made. It has to be in early July.

[Richard S.]

Re: vin#/birthday book

13904 was born Wed. July 1st, 1970.

[robert leazenby]

thanks a lot, i appreciate all! *NM*

[Juliet P.]

Re: thanks a lot, i appreciate all!

Neat thread. Robert, your build date / VIN fits fine in sequence with other 1970 Corvettes in the registry. :-) You can see your vehicle specs as you provided them to me here: http://corvetteforum.net/c3/1970registry/1970Reg7.html

We also have some other production information which we've derived from the 300+ vehicles in the registry. It can be found in the Statistics section of the web site. http://corvetteforum.net/c3/1970registry/BuildDays.html

~Juliet

http://corvetteforum.net/c3/1970registry/