Differential Covers 63-79

[Dick W.]

I have quite a few differential covers and have noticed a difference in the castings. Some have a center rib on the rear and some do not. Can I venture to guess that the ones without the ribs are earlier cars? If so, when did they add the rib?

[Wayne M.]

Re: Differential Covers 63-79

Dick -- here's two; a "303" cover off a Jan '64 assy. (has rib). a "375" cover off a July 15 '65 assy (with rib). Pic is off a Sept '64 diff; another "303" with rib. Sorry, no newer examples.



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[Joe L.]

Re: Differential Covers 63-79

Dick-----


As far as I know, all of the 1963-77 covers had the reinforcing rib. These include the '303' and '375' covers. It's possible that the 78-79 cover, cast 464910. did not have the rib. I have an NOS example of this cover but I can't get to it right now.

[Dick W.]

Re: Differential Covers 63-79

Thanks Joe, I will get the casting# tomorrow.

[Tom R.]

Re: Differential Covers 63-79

Dickie

I'll have my 78 up on the lift today and the tub is off so I can shoot a pic and post if that will be helpful.

[Joe L.]

Re: Differential Covers 63-79

Dickie

I'll have my 78 up on the lift today and the tub is off so I can shoot a pic and post if that will be helpful.

Tom-----


Photos are always helpful, so post if you can.

In this case, there is another recent thread involving a photo of a 464910 cover (one that was installed in SERVICE for a 1968 Corvette). This cover has the reinforcing rib as I would expect.

I'm very interested to see what Dick comes up with regarding the casting number on the piece in question. If such a non-ribbed GM cover exists, all I can surmise it might be would be an early version of the 3830303 cover limited to use in the 1963 model year only or some unknown casting number. Normally, a change like the addition of a rib to a casting would result in a new casting number but it's not beyond the realm of possibility that a revision occurred within a single casting number.

[William L.]

Re: Differential Covers 63-79

Dick this is off of my June 67 B/B

[Gary F.]

Re: Differential Covers 63-79

Here's 2 from 63. The light colored one is a Series 3, and the black colored one is Series 4. Both are middle of the road.

[Tom R.]

Re: Differential Covers 63-79

I'm not sure if the TDB took it or not so I am posting a 2nd time. The casting lacks some clarity but I can shot another if we need clarity.

DSC03107.jpg

[Harry S.]

Re: Differential Covers 63-79

100_1805.jpgAnother view of a 303.

[Kenneth S.]

Re: Differential Covers 63-79

The original from my '63 dated 4-8-63

63 Differential.jpg

[Harry S.]

Re: Differential Covers 63-79

Ken, fine thread or course threat on the drain plug? In the picture I posted it's a GM 3 cast with the fine thread.

The original from my '63 dated 4-8-63

[ATTACH=CONFIG]36400[/ATTACH]

[Wayne M.]

Re: Differential Covers 63-79

Ken, fine thread or course threat on the drain plug? In the picture I posted it's a GM 3 cast with the fine thread.

Harry -- I believe that the "303" covers were tapped for coarse thread for early '65 (my 014xx, AP-9-17-64, for example, pic below), or maybe later '64's, depending on any others reporting.



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[Kent S.]

Re: Differential Covers 63-79



April '63 car

[Jerry G.]

Re: Differential Covers 63-79

Anyone ever hear of an aluminum rear cover with GM part number 0228635. issued by GM to factory racers in 63/64?