Phillydog

I have a 1969 Stingray. It appears to have the original 350cid/350hp engine. However it also has the M40 Automatic Transmission option. The problem is that all of the information I've seen on the 1969 Stingray builds indicates that no 350hp engine vehicles were manufactured with the automatic transmission. The 350cid/300hp and the 427cid engines were available with the automatic transmission. I contacted Chevrolet and their historical information confirmed these facts. Although I don't have any of the original vehicle information, I had a replica window sticker made using my VIN as a reference. The replica showed this vehicle to be built with both the 350hp and automatic transmission options. Can anyone shed any light onto this anomaly?

Easy Mike

It is my understanding the L-46 350hp engine required the four speed. What is the engine suffix code on the pad? No disresect, but a replica window sticker is an unrealiable source for confirmation. Most of the folks creating the replica documentation rely on you to tell them what to print. The VIN contains no information concerning options on the car.

vettebuyer6369

When you say the engine "appears" original it tells me you might not really know. Check the block number, casting date and pad information. (assy code and VIN derivative)

The '69 NCRS JG states the Turbo Hydramatic production code is stamped on an identification plate located on the passenger's side vertical surface of the trans case. This contains model year, model identification & production date. Below the production code is the source serial number.

These 2 areas or numbers need to be reviewed to answer a lot of your questions.

Mike Ward

The people that make the replica window stickers will put whatever info you want. Wanna see a '73 L88 with M22 and heater delete sticker?

Your car did not come from the factory with an automatic transmission if it is an 350/350 L46.

Phillydog

Thanks Mike for your reply. I have little original info that came with the car. I'm at least the 4th owner and am trying to figure it all out. The badging on the console is the 350/350 and has the correct compression ratio for the 350hp. The carburetor number matches the 1969 Stingray 350hp engine. It is definitely the 3spd automatic transmission.

vettebuyer6369

Again, carbs are easily changed. Console plates have 4 screws. What's the Tach redline?

Check the engine pad info and the trans #.

Red Vert 02

Phillydog,
First off welcome to the Forum. Congrats on your '69. They are great cars. As others have said no L46 engined Corvettes were built at St. Louis. That's not to say a dealer could not have done the conversion to make a sale. The console plate with the engine info is easily changed and all the Corvette parts houses have them. The L46 carb # 7029207 became the service replacement carb for many 350 ci 4bbl Chevy engines equipped with Qudarjets. It was available through Delco into the late 1990's. They occasionally show up on fleabay brand new in the sealed box. The tach red line should be 6000 for the L46 engine. There are no characters in the 1969 VIN that indicates which engine or transmission a Corvette was originally built with. That did not start until 1972. The 300hp and 350hp engines used the same air cleaner with chrome lid. The 300hp used stamped steel engine color valve covers, but they are easily changed to the L46 finned aluminum covers. The L46 valve covers are sold by all the Corvette parts houses.

Alan 71

Hi PD,
I'll say welcome TOO!
Another thing to check will be the frame crossmember at the rear of the transmission. The cars with an auto trans have a bolt-in crossmember, while the 4-speed cars have a welded in place crossmember.
You might look to see what's going on where the crossmember meets the frame rails.
We like to see pictures of cars we haven't seen so.....
Regards,
Alan

Happy New Year!

Easy Mike

The engine identification suffix on the pad will identify the engine. Since the VIN derivitive is stamped beside the engine code, you can easily determine whether the engine is original. Jot the numbers down and post them here.

Phillydog

Thank you all for this great info. I will digest it and it will all make sense. I am a novice at this and I'm not sure where to locate the engine ID number. The tach redline starts at 5300 and goes to 7000 for this vehicle. The cylinder covers are the finned variety. I will try and locate the engine ID number and post it. I do understand that the suffix will identify the engine type.
Thanks,
PD

zwede

5300 rpm redline sure sounds like a base engine.

Easy Mike

There is a pad on the block at the front of the passenger's side head. AC and AIR pump may make it difficult to see. It may have road gook on it. Two numbers are stamped on the pad. The first identifies the engine and the date it was assembled (VxxxxXX). The last pair of characters are alpha. The second stamp is the VIN derivitive of the vehicle the engine was originally installed in.

Here's the pad from a 68. Your 69 will be similar.



Easily changed.

Wanna drool? Pricey, but pretty good.


Dr. Dobbins' book is also good.

7T1vette

From the Corvette Black Book, there were no automatic transmissions behind any L46 for both 1969 nor 1970. If an M40 could have been installed with the L46 in a 1970 model car, and your car was produced late in the '69 model year, there might be some chance that it could be 'real'. However, the 1970 models did NOT put the auto with the L46, either. Don't think yours has a real L46.

Most likely, it is a base model engine (L48) with finned aluminum valve covers. If the 2 letter suffix code on the engine VIN pad is correct for an L46 engine, then the engine pad was "re-stamped" or the M40 is a replacement for the 4-speed that came with the car.

P.S. The reason GM didn't put M40 with L46 is because that engine (and the later LT-1's) could achieve high RPM redlines. That elevated RPM could have caused M40 torque converters to fail [explode]. It could take the added horsepower and torque...just not the RPM's.

vettebuyer6369

engine block casting number on dirty, oily '69:



engine block number (clean, painted '58):



engine block casting date (tanked, clean block):



engine assembly code with prefix, MM/DD date and suffix and VIN derivative found on pad as pictured in previous post by Easy Mike.

I'm going to guess that your engine is a replacement.

Phillydog

Wow thnx to everyone for this great info. I will investigate further using the advice provided by the contributors to this forum string.
Regards,
PD

Mike Ward

Meant to say casting number, not serial number I bet.

Phillydog

okay thanks Mike.

vettebuyer6369

Yes, expended all my brain cells posting the photos.

TimAT

You could have a beer. I've been told that helps repair strained brain syndrome..

Ratfinkharley

Beer does make you smarter; it made Bud wiser.