I've been a reader for a while and have wanted a 454 Chevelle even longer.

I finally bought a 70 with an LS5. It has a build sheet, but only part of the original drivetrain. It needs restoration and I'd like to restore it as close as possible to original.

I need to find an original/correct transmission and rear end. The car was built in June of 70 at the Baltimore plant with a sequence number that starts with 202xxx. It came with an M22 and a 4:10 posi rear. I know the correct part codes for those, but I need to know what date codes I should be looking for.

If anyone has a 70 454 that was built in Baltimore with a sequence number close to mine that has an M22 and/or a 4:10 posi rear could you please help me as to what date codes I need.

Erik

I was thinking of my other 70 Chevelle, a 396, when I listed the automatic. The 454 has the M22.

Erik

Erik,
I makes no difference what plant the Chevelle was assembled in as the transmission and rear end were sub assemblies that were supplied to Chevrolet. Muncie was the only plant for the trans but there were three for the Axle assembly for the rear end. Detroit Gear, Buffalo, and Warren. I have been told and to some degree confirmed that the transmissions and the rears were assembled in groups meaning they would make a run on say CRW (4:10) coded rears on a specific date and then move onto another code. Unfortunately, I have not gathered enough info on this so far to give you a definitive date for the rear end. Most of the later 4:10 cars I have documented had mid March assembly dates.

As far as the transmissions, the case was shared by the whole 4-speed line so that would not matter but the cars VIN would be stamped on the trans. Obviously there is a little you can do about that if your original is missing. However, there is a code stamped on the case as well something like P0C23 that I believe were also run in lots.

Hopefully (anyone) with a 4:10 CRW coded rear can chime in and tell you what assembly dates they have. I will look in my records as well and see if I can be of further help.
Rick

Rick,
Thanks for the reply and the info. Yes, the car's original transmission and rear end are no longer with the car. If I understand correctly, both the trans case and the rear axle housing were made in batches. So, for example, the correct trans case for my car may have been made the first week of March and then again second week of June. Same for the rear; 4:10 rears may have been made in January and again in April.
So, knowing that helps a little. Though, I still need to determine which dates were being installed on the cars when mine was being built. Are any of the cars you mentioned close to mine?
Thank You.
Erik

Erik,
My understanding is the cases were not made in batches but rather the entire assembly was made in batches as there is no difference in the base castings from one series to another. These were done on specific dates. They would run a batch of say 3:31 for a few days and then switch to say 4:10s. Same with the M-20, 21 and 22. If anyone else has any input, it would be helpful.

I have a ton of information on 454 cars but will admit that I have researched the rear ends very little as far as assembly dates. Perhaps "Crash" can be helpful on the transmissions as he has had thousands of cases.

Mike "elcamino" may also be able to shed some light on the rear end dates or the process. I will try and get you some info as soon as I can. I am leaving town for about 10 days and likely will not be able to go through my stuff until I get back. Hopefully one of the many 70 Chevelle gurus can chime in and help in the mean time.
Rick

I have an LS5 that was built in June 70.
It has an M22 and as far as I know it's
the original. The date code is P0E01C.
Hope this helps.
Greg

Have a POP from a LS5 Baltimore-built in April with a February 19 dated CRW rear (CRW0219B) and a February 11 4-spd (P0B11)

Another POP from a LS6 Kansas-built in April with a March 17 CRW rear (RW3017B) and March 23 4-spd (P0C23)

Note the POP doesn't denote A, B, or C suffix for M20, M21 or M22 trans type.

Just got back from the holiday. Thanks for the responses. They are good examples. The trans code from blueline just about answers the question for that part.
Dale, any chance the axle housing casting dates from the rears you mentioned are known? From what I've learned, I'll need to know both the casting date and the stamped part assembly date to have a part that's as correct as possible.

Better yet, anyone else out there have a June Baltimore car with a 4:10 rear?

Erik

OK, from what I was just told, I don't need to know the casting number for the rear end. All I need is to determine the stamped date. Is this true? Any help is appreciated.

Erik

Erik,
It is still important that the rear axle has one of these two castings for a 70 Chevelle. (I have seen a 3959038NF on a 70 Chevelle)
1969 Chevelle 3959038NF
70-72 Chevelle 3969278NF

Just make sure the CRW date code corresponds somewhat with the assembly date of the overall unit.