67 saginaw casting numbers

[Keller-L30M20]

I'm new to this site and not sure how to do this, but here goes. I've recently picked up a barn find M20/L30 RS #124377N1XXXXX in the upper Midwest with 38,000 miles that seems to be an early car that the 4P was not on the cowl tag. Cowl tag says built 5th week of October. It has a MK date proper block, heads and intake, 3.55 10 bolt PK code non-posi rear end, dealer installed radius rod (dealer welded bracket right over the date code). Also has the original carb and shifter were in the trunk (has a Holly and Hurst on it right now) The problem is like most M20/L30 cars the prior owner had blown the trans and replaced it with a 1974 Saginaw 4 speed trans. I real would like to put it back to 100% original but need to find out what the proper numbers are for the trans. CRG lists the main case number (3915032) but nowhere could I find what the proper side cover and tail shaft numbers are. I have a line on a date proper 6 cylinder 4 speed that has the case number but not sure it the side cover and tail shaft are the same numbers V8 trans. I know the gearing is different for a 6 banger but I would rebuild it with the proper ratios.  Any help would be appreciated.
Also, Thank You. Your site is a world of information and has helped me a lot. Keep up the "great work"

[Kelley W King]

I did not think the gearing was different?

[Keller-L30M20]

All 6 cylinder motors had a 3:11 first gear and the L30 trans for V8s was a 2:54 1st gear

[bertfam]

Yes, the gearing is different between the 1967 230 and 250 6 cylinder Saginaw 4 speed transmission and the 1967 LF7 (327/210) and L30 (327/275) V8 Saginaw 4 speed transmission. The gearing is as follows:

230 and 250 6 cylinder
1st - 3.11
2nd - 2.20
3rd - 1.47
4th - 1.00
Rev - 3.11

LF7 (327/210) and L30 (327/275)
1st - 2.54
2nd - 1.80
3rd - 1.44
4th - 1.00
Rev - 2.54

The 1967 Camaro main case casting number is 3915032, the extension housing is 3860042, the side cover is 3890527 and the front bearing retainer is 3859033. Note that the 6 cylinder Saginaw 4 speed transmission casting numbers are the same as the V8 Saginaw 4 speed transmission casting numbers. Only the "guts" are different.

Oh, and welcome to the site Mr. Keller! Tell us more about the car.

Ed

[Keller-L30M20]

Thank You, Ed. I'm the third owner. the car was in a dirt floor barn in northern Wisconsin for the last 15 years. Surprisingly there is very little rust on it. some minor swis-cheese in the trunk floor and a couple of 1/2 dollar holes on the bottom of the rear inner wheel wells, other than that just a lot of surface rust on the under chassis. It was repainted back in the late 70's or early 80's. Who ever did the paint job did a really nice job cause the only thing I might do right now is repair the upper valance where its chipped and buff the rest of the car out. It's a black car with the original black vinyl top,with a few small rust bumps at the back bottom of the sail, but no dry rot; black & white interior with the back fold down seat. It has the full factory console gauge setup with the Tac in the dash. I got wind of it through the grape vine and made a move on it. I guess right place, right time. I didn't steal it but by far didn't over pay for it. Thanks for asking, Frank

[bertfam]

Ok Frank, you're going to have to post some pictures! It sounds like a really nice car.

Ed

[olddragracer]

I believe the 1967 Saginaw 4 speed was redesigned during the 1967 production. The case, cluster gear and all the parts involved with reverse are different and not interchangeable. I am not sure when during the year the change occurred. This info is from my memory.

[bertfam]

The main case and side cover casting numbers changed for the 1968 model years, which began in August of 1967, but that's the only thing I can find.

Ed

[olddragracer]

I have just checked my Feb. 1970 Camaro parts catalogue. The Saginaw transmission case part number for 1967 3 and 4 speeds "FIRST JOBS" is 3890566. The 4 speed "AFTER JOBS" case part number is 3925654. I do not have the original casting numbers or the date of the design change. The improved reverse idler gear made it necessary to change the case, reverse shift lever, 1st -2nd synchronizer assembly with reverse sliding gear and reverse idler shaft. There were other changes to improve the transmission. The side cover changes in 1970. Saginaw 4 speeds were used in Vega to trucks so there are many variations out there. More research may be necessary but I hope this helps.

[Keller-L30M20]

What your saying is the number that CRG has for the main case number is wrong. This is where I'm getting a little confused. I'm getting mixed answers. The cars build date 10E was actually Monday Oct 31st so the car was built the first week of November. Therefore the case was most likely cast sometime in August or September and the trans would have been built somewhere between Sept and Oct of 66. Everything on this car checks out to be original except the trans, muffler and tires. I know these were notorious for being blown and then switched out for a Muncie. At least one of the prior owners that blew the trans put a Saginaw back in it. You mean to tell me there are no original L30/M20 cars out there to verify what trans went in to it

[olddragracer]

The numbers I supplied are part numbers as of February 1970 and are different from casting numbers. I am trying to point out that in 1967 production there are at least two different castings used for the main case. I am not sure when, as the parts catalogue calls "AFTER JOBS" were installed on the production line. Looking inside the transmission The "FIRST JOBS" reverse idler is 1 1/2" long and the "AFTER JOBS" reverse idler is 2 1/8" long. The reverse main shaft gear "FIRST JOBS" gear teeth are partial width of sliding sleeve, "AFTER JOBS" the gear teeth are full width of the sliding sleeve.

[Keller-L30M20]

So more than likely 3890664 would be the main case for this car?

[Keller-L30M20]

Thanks ED, I also tried to upload photos but couldn't figure out how. Whats the secret? Or I can e-mail them direct to you. Frank

[bertfam]

Yes, go ahead and email them to me. My email address is in my signature below.

Ed

[olddragracer]

Of some interest. In my observation, over the years, the part number is often one or two numbers higher than the casting number. In this case, casting number is 3890564, part number is 3890566