Our 1960 Monza Coupe

[jmiahman]

Thought I better start a thread for this project my son and I have started on. My son and I have already dug a bit into it and found some fun stuff that kinda has made this thing a bit of a mystery or just a more unknown model year as a 60. So far we have just torn down the engine. I have had a hard time finding information on a lot of these parts so I thought I better post what I have found so that it might be a help or at least a confirmation for others you might be in the same boat I am.

VIN = 00927O135428
Body Tag:
CHEVROLET DIV. GENERAL MOTORS CORP
06D DETROIT, MICHIGAN
STYLE 60-0927 BODY OA 709
TRIM 1-882 22 PAINT 926
ACC. 2 6A ----8394
THIS CAR FINISHED WITH
Magic Mirror ACRYLIC LACQUER
BODY BY FISHER

Engine Serial (Supposed to be 95HP 4-Speed):
T0602YD (June 2nd, YD = 95HP, 4-Speed)

Crankcase Part #s:
6255616
6257621

Crank:
5607

Cam:
3777255

Heads:
3777238

Pistons:
6255631

Bell Housing:
6256583

Transmission (Not Original 3-Speed)
Date code: D123 (March 12th 1963)
Case# 3826176

Differential:
Date code: B660 (6th day of June?)
3780263
BR6 6 (Type BR 6th day of June)

Valve Springs:
3735381

Hope this helps someone else. Obviously the transmission isn't original [1] interesting whatever was on it was replaced in just 3 years. A lot of the other parts seem to have fairly early numbers that would coincide with a 60. Maybe this will show up in Google searches for other owners and be a bit less of a mystery. I have found the GM Parts Wiki [2] to be a great resource as well in checking some of these numbers to make sure I read them right and they did exist lol. If there are any other numbers I should add for this car that would be helpful for others please let me know. I also ordered a parts number printout from Clarks, but they didn't have most of these numbers recorded I reached out to them about the YD engine for 60 not being on there and they confirmed it at least existed on paper and that their list may not be complete or accurate. Thanks.

[1] https://www.corvair.org/chapters/corvanatics/codes.php
[2] http://www.gmpartswiki.com/browse

[Phil Dally]

The sixth digit in the VIN is an O not a zero.

Meaning built at the Oakland Assembly Plant.

https://en.wikipedia.org/wiki/Oakland_Assembly

[jmiahman]

Yup along with the OA in the Body Tag its a west coast car, the Corvair was the last model to be built at the Oakland plant, it closed in 63. It's replacement Freemont never made Corvairs but they did make Chevy Celebrities, that was my first official car and Celebrities were Fremonts last as well.

[joelsplace]

Why would you think the transmission was replaced in 3 years? I can't imagine anyone buying a brand new transmission for a 3 year old car. It could have been replaced 50 years later.

[cnicol]

Jeremiah, would you mind posting a picture of the center section of the rear suspension cross member where the transmission support bolts on? This area should be exposed since the transmission is out.
I am interested to see what GNM did to accommodate the longer 44-speed transmission.

[jmiahman]

Why would you think the transmission was replaced in 3 years? I can't imagine anyone buying a brand new transmission for a 3 year old car. It could have been replaced 50 years later.

You're right maybe it wasn't 3 years, but the car was parked in 78 and was untouched in my grandparents backyard for 46 years. So you're right anywhere in those 15 years after 63 it could have happened.

[jmiahman]

Jeremiah, would you mind posting a picture of the center section of the rear suspension cross member where the transmission support bolts on? This area should be exposed since the transmission is out.
I am interested to see what GNM did to accommodate the longer 44-speed transmission.

I can but the only thing I have noticed are the normal shims (a few) on my current train setup, however there was a redesign to my knowledge for the transmissions when they went from aluminum in 61. So not quite sure on the 4-Speed size to make that assumption as it wasn't the same 4-Speed supposedly that was placed in 61s and later. I really don't know if it was a 4-Speed because of the aluminum casing issues they had with the 3-Speed it may have never had it or been quickly replaced. I have talked to one other person (Pete) who supposedly owns an Aluminum 4 Speed but it was not factory, maybe I should get him to measure his and that would remove all doubt. If not there's supposedly going to be one in the Ypsilanti Corvair Museum in the next few months. I would love to drive there and see it. So even though this was supposed to have RPO 651 it may have never had it, though my shifter matches what should have been a 4-Speed according to the 60 Assembly manual. I still have no problem posting a picture if you still want it.

[cnicol]

Thanks, Jeremiah.
A couple of related factoids...
-Corvairs were originally supposed to be "automatic only". The adaptation to a manual trans (Chevrolet's non-syncromesh 1st, 3-speed) was something of a "crash program" already. That's why our flywheel is so weird.

- The Corvair 4-sp was GM's first passenger car four speed design so they knew they had to get it right, even if it meant delay. Previous factory 4-speed equipped GM passenger cars used a four-speed outsourced and purchased from Borg-Warner, sometimes alternatively known as "Warner Gear". Of course the rear-wheel drive Borg Warner unit wasn't going to work in the rear engine Corvair. After the Corvair 4-speed, GM's second 4-sp design was the 1963.5 "Muncie" 4-sp, which replaced the outsourced Warner T-10 4-sp.

- While the associated components and literature were ready, the aluminum case 4-sp had a potential problem because the aluminum case 3-sp was suffering from casting issues. Taking a chance on the aluminum 4-sp wasn't worth the risk. In my understanding, the aluminum case 4-sp was simply revised to cast iron in an identical size.

- The 4-sp takes a different-ratio shift lever as indicated by a shorter, floor-mounted, shift tower. 4-speed Corvairs also had a revised shift lever with a 90-degree turn to the rear.

-The 4-sp transmission is longer; so much so that the transmission cross-member had to be "notched" for clearance. Your car either has: 1) no notch 2) factory notch 3) home-made notch. A photo would indicate which conversion it had, if any.

Below: A stock 3-sp or PG cross member. Note the flange along the bottom and flat vertical face above it (left to right) Ignore the saw cuts.

Next: a stock 4-sp cross member cutout for the 4-speed transmission.

Next is a 3-sp/PG cross member modified (by me) for a 4-sp. Other guys (and gals) make the mod other ways including a simple, flame-cut hole! With my method the flange is gone and the vertical wall is pushed forward at the bottom half an inch or more.

[jmiahman]

This is awesome information, I would think there would be differences between Iron Casting and Aluminum structure and strength considerations but maybe they could be identical. I'll take a look now that I know what to look for and post pictures. Thanks again.

[jmiahman]

Okay I am posting some pictures, from my model it doesn't seem like a notch would have made much of a difference as it's pretty flush to the cross member on the body it attaches to. Does the body have a notch as well? Are there any pictures of a 4-speed mounted to compare?

I don't have anything to compare to so it would be nice to have a reference. Here's the picture of the shifter.

[jmiahman]

Also that Stock 4SP cutout picture doesn't match anything I have seen in my research looks to be a blown-up picture from here:
https://corvaircenter.com/forum/viewtopic.php?t=176029

which if I understand correctly is modified and still needs some work for strength. I would have reinforced it a bit more as well don't think that's factory. Your modification looks much more legit.

[cnicol]

Also that Stock 4SP cutout picture doesn't match anything I have seen in my research looks to be a blown-up picture from here:
https://corvaircenter.com/forum/viewtopic.php?t=176029
which if I understand correctly is modified and still needs some work for strength. I would have reinforced it a bit more as well don't think that's factory. Your modification looks much more legit.

Oops. I posted a home-modified 4-speed crossmember by mistake. My bad. I've revised my post with a photo from California Corvairs. Their red arrow points to the area GM Factory-modified for more room for a 4-sp. Oddly photos of the factory 4-sp crossmember are hard to find on the internet.

Your car's crossmember is a 3-speed/PG type; it does not have a relieved area for the longer 4-sp. The shifter base is the taller 3-sp type, the shift lever is the straight 3-sp type, the shifter lever is black paint as found in a 3-sp.

There's no change in the body for the 4-sp.

Another 3sp/4sp clue is the reverse light switch. In a three speed, the switch is in the middle of the tunnel with a tab on the shifter rod. In a 4-sp there's a long 2-wire cord (black and white) plugged into that location and running off to the transmission which has a switch at the lower front. Remnants of this cable would be there and of course no tab on the shifter rod.

[jmiahman]

Also that Stock 4SP cutout picture doesn't match anything I have seen in my research looks to be a blown-up picture from here:
https://corvaircenter.com/forum/viewtopic.php?t=176029
which if I understand correctly is modified and still needs some work for strength. I would have reinforced it a bit more as well don't think that's factory. Your modification looks much more legit.

Oops. I posted a home-modified 4-speed crossmember by mistake. My bad. I've revised my post with a photo from California Corvairs. Their red arrow points to the area modified for more room for a 4-sp. Oddly photos of the factory 4-sp crossmember are hard to find on the internet.
used-1961-64-rear-cross-member-4-speed.jpg

used-1961-64-rear-cross-member-pg-3sp.jpg

Your car's crossmember is a 3-speed/PG type; it does not have a relieved area for the longer 4-sp. The shifter base is the taller 3-sp type, the shift lever is the straight 3-sp type, the shifter lever is black paint as found in a 3-sp.

There's no change in the body for the 4-sp.

Another 3sp/4sp clue is the reverse light switch. In a three speed, the switch is in the middle of the tunnel with a tab on the shifter rod. In a 4-sp there's a long 2-wire cord (black and white) plugged into that location and running off to the transmission which has a switch at the lower front. Remnants of this cable would be there and of course no tab on the shifter rod.

Not a problem, just for sanity sake I want to make sure. Also a bit a go I looked on California Corvair for the same thing you have and noticed the crossmembers were for 61 and beyond. How are the Crossmembers different then the 60? Why isn't the listing from 60-64? I also read the splines for the 60 Aluminum 3 Speed Transmission was different then later 3 Speeds and should meet up with a 60 Differential, is that true as well. The Transmission is a 63 has anyone ever put/replaced an aluminum 60 transmission with a cast iron not having to change the crossmember and Differential? Doesn't seem like they were drop in replacements. The 63 transmission I have and what I have read has me confused on multiple levels and I'm trying to come to a rational process that was done on the car, and what I may need to fix, or deal with not working quite right.

[cnicol]

Craig's comments in blue

Not a problem, just for sanity sake I want to make sure. Also a bit a go I looked on California Corvair for the same thing you have and noticed the crossmembers were for 61 and beyond. How are the Crossmembers different then the 60? Why isn't the listing from 60-64?

Almost every mechanical part on a '60 is unique to the '60 model. As shown below, the '60 crossmember has a one year only reinforcement bracket. There are probably other differences too.

60 CrossMember MU.jpg (100.12 KiB) Viewed 274 times

I also read the splines for the 60 Aluminum 3 Speed Transmission was different then later 3 Speeds and should meet up with a 60 Differential, is that true as well. The Transmission is a 63 has anyone ever put/replaced an aluminum 60 transmission with a cast iron not having to change the crossmember and Differential? Doesn't seem like they were drop in replacements.

When changing from an aluminum 3-sp to a cast iron 3-sp, I believe (not sure) you have to change the differential as well because of the spline thing. When installing a later 3-sp you DO NOT have to change the suspension crossmember or transmission support bracket.

The 63 transmission I have and what I have read has me confused on multiple levels and I'm trying to come to a rational process that was done on the car, and what I may need to fix, or deal with not working quite right.

It seems to me, based on your engine code, your car was intended for a 4-sp but parts were not available so it was built with a (likely aluminum) 3-sp trans and shifter. Somewhere along the way, someone installed a later transaxle with a cast-iron 3-sp. This would be a bolt-on solution that would fit the 3-sp suspension crossmember without need for any modification.

[RexJohnson]

The mainshaft of the aluminum 3sp only splines into the pinion shaft of the diff by an inch or so. Very short compared to the 4" or 5" that the '61 and later ones do. The splines on the '60 mainshaft are very course like maybe 10 so even if the length was the same they wouldn't mesh together. Another thing on a '60 diff is that both stub axles are the short ones. All of the later ones have one long and one short. If you check your axles I'm betting that you will have 2 different lengths. Something could have failed on your transaxle or maybe someone wanted to change the axle ratio are reasons why yours could have been changed.

[Frank DuVal]

A friend has a '63 with an aluminum '60 three speed installed. The crossmember looked "normal" for an early three speed to me. I tried to sell him a four speed with crossmember, etc., but he liked the odd aluminum three speed. He now lives in Florida if anyone sees an aluminum three speed '63 down there, it is the same one probably.