Recently purchased a 1974 corvette. 454, 4 speed, orange coupe. Vin 1z37z4s408814.
Engine numbers found in various areas: J18 73, T1031 CWR 148408814, 8999289. The CWR is supposed to be 454 tubro hydra-matic? But mine has a 4 speed.
Transmission numbers found in various areas: GM 3846429, 464697, DC, 9183, 3&4 Sel & Sink Gask, 3851325 US Patent no 3088336.
The build sheet was on tank but in very poor condition. Did manage to barely read some letters and numbers but can't read the box they are in or descriptions. Going left to right, top to half way down: 976, CWR, S, AW, 62-0916 11-2, MG, 21, 318, S, K, 429, RH, DK, AF, AR, AH,UK, BN, GH, UN, EL, U5 N, MC, 205, CV MSAD, 1YZ37 416, BRKS, BC, CX, LDG. Had to use magnifying glass and strong light. May have missed some letters and numbers and misinterpreted some. Has an AW (308?) rear end code which seems high for a four speed.
Thank you in advance for any help. Rick

 

Rick

I can help with a couple of your numbers

J18 73 - is your casting date for the engine block - Oct 18 1973
T1031 - is the location and assembly date of your engine - Tonawanda Oct 31
CWR - is the engine code - 270HP 454 CI engine mated to auto trans
148408814 - is your partially vin - engine appears to be original to car
8999289 - is the engine block casting number - this is the correct block casting for 1974 cars

I'm not familiar with the layout of 1974 build sheets so I won't make any guesses for that.

1YZ37 - base Corvette sport coupe. 1YZ67 was the code for convertibles.


The 3.08 rear end was available with the 4 speed wide ratio (M20) transmission but your engine code is for an auto. Does you car have a welded or bolted transmission cross member on the frame? Welded was used for manuals and bolted for autos.

John

 

The code usage in 73-74 was a little scanty but still reveals fascinating information. If you can scan, not copy, and post or send me a copy, I can better align the codes with the data field description. Sent to hunt4cleanair@earthlink.net

Some I would have to see their placement on the sheet. As you can see, code placement is not consistent but skips boxes. But here are a few guesses:

CWR - 454 w turbo hydra-matic
S - transmission code (?)
429 - starter code for automatic (last three digits of the part number)
AW - axle code 3.08:1 posi
MG - front spring code
RH - rear shock (I think)
21 - steering knuckle
318 - last three digits of the front stabilizer bar
MC - radiator code
MSAD - interior - steering wheel/column color - saddle
1YZ37 - base coupe model code vs convertible (row marker)
416 - saddle leather trim code
BC CX - master cylinder broadcast code (?)
BRKSW - break switch

62-0916 11-2: I believe this set of numbers (upper left corner of sheet) is your schedule number (first set) and the expected date of production. The 11-2 would be interpreted to indicate this vehicle was expected to start production November 2nd...how does that align with the date code on the trim tag?

The 62-0916 would be schedule # 62 and asigned job number 916. If you look on the passenger side, underneath footwell, you may be able to see the 916. Its the job number...If my interpretation is correct.

This is a start...I'll post more if I can dicipher.

I have not seen that many 74 build sheets but it looks like those AF, AR, AH etc may be belt codes...depends on where they are located on the sheet.

 

In regards to the four-speed, if you do a search (here on the forum), you should find some references of where to look for the date code and VIN derivative. The VIN derivative is an abbreviated serial number that was stamped onto a transmission and is the "matching" number to the engine serial number. This would help reconcile the mismatch between engine code and starter code. You are looking for stamped series and not the embossed casting numbers.

 

14S408814 Alpha S plant code for St. Louis.

 

This may help out a bit.
http://www.corvsport.com/Corvette/C3..._1974_VIN.html

 

Alan...is that WD a double strike? I take it from the post by labhound of the 1974 data composite that the broadcast code for the 4-speec is WD...this is a nice resource! Of course webhost calls it a "type designation" and probably not familiar that the correct reference is broadcast code.

 

Cross member is bolted. Cross member is just behind the transmission mount. No signs of any welding where cross member attaches to frame. Does that mean it did not come from factory that way?

 

Trying to upload picture of build sheet. Only what I can barely see, I used a marker on a copy to high light.

 

Rick

Unless the frame has been replaced, if your transmission cross member is bolted it signifies that the car originally had an auto transmission. Manual transmission cars got a frame with a welded cross member.

Auto transmissions are much larger than manuals so the bolted cross member helped with assembly/servicing the unit.

Another thing to look for to differentiate if it was originally an auto or a manual transmission car is to look at the passenger side foot-well next to the transmission. Since the auto was larger the factory would cut out part of the floor board and bond in a new piece that would allow the auto to fit. You should be able to see this from under the car or with the carpet pulled back.

John

 

Ricky

So you listed your VIN derivative (engine) as 14S408814 (corrected per Easy!). But on your copy posted here, in the upper right-hand corner I read 148219 which is the box where the serial number is typed by the tag station worker once the VIN tag is assigned. Am I correct in my reading and placement of this number.

Also, you list the EL code in a position on the sheet reserved, I believe, for the CARB broadcast code. The NCRS manual reports an FL code for the carb matched to a 454 automatic tranny power team. Is it possible, due to ineligibility, that this is an FL code? This will confirm the code and that it left the factory an automatic.

Look on the carb, driver's side, shoot a picture of the stamping and post. It should match with your buildsheet...Carbs were equipped based on power teams.

RH - Alternator code for 61 amp GM# 1102353...check your alternator for this part number! This was equipped with LS 4 and A/C...do you have A/C?

Love this stuff!

I think I should have a new title...buildsheet forensic examiner!

 

Rick

From what I am seeing here...your suspension is a standard suspension but due to the LS4, you got the beefier front stabilizer bar. I don't see a code for the rear bar.

 

John. It does appear to be patch work in that area. It appears to be a different color than the rest of the floor. Is almost black in color.

 

The 14289 number is in the upper right corner. Checked again and yes that could very well be an FL. Alternator number is 1100834.

 

All the codes you see in photo is all I could read. Will try to upload a photo of rear suspension. Rick