400 Main bearings

[Nacho-RT74]

What’s the difference between MS876P and MS1348P bearings?

 

[Vaanth]

In 1974, a production change was made to increase the number three bearing thrust face in both 400 and 440 engines. Both engines from then until the end of production after 1978 used the larger thrust bearings.

The bearing set MS1348P contains the larger thrust bearing for 1974 -1978 400 engines.

The bearing set MS876P contains the smaller thrust bearing for the limited 1971 release 400 engines, 1972 - early 1974 400 engines, and earlier 383 low block, 361, and 350 engines. This set can be used in the later engines but there will be a mismatch in the thrust face of the crankshaft and bearing.



The following images show the TSB describing early 1974 engines using the smaller bearing and later using the larger bearing:

 

[Nacho-RT74]

Ok so the thrust width is the diff! I thought it could be something else!

I was aware about that diff existed, but I thought the 876 was already with the larger thrust surface.

Sooooo Is about the year but not the casting number…

 

[Nacho-RT74]

Does somebody knows the width of the machined surfaces on each one?

I had to replace my block. Got a correct year block (74) for my 74 Charger, but it got missed the main caps. Found a 73 block donor where I removed the main caps ( yes, I know caps must be machined with block to seat correctly the crankshaft… was already done) but I think machine shop didn’t realize this difference on the thrust bearing size and I’m 6.5K miles away. Mostly sure it got the smaller machined surface and I’d like to get a full matched 74 assembly (aside the thicker thrust bearing set uses to be a bit cheaper). I all have found the full outer diameter of the bearings itself. I guess the machined area must be a tad larger than the bearings.

Yes, I know maths can be made, but just for double check.

 

[PRHeads]

It’s not the “thickness” that’s different, it’s the OD of the flange.

You can use the early(small flange) bearings in early or late blocks.

Depending on the capabilities of the shop that installed the caps, if the block was factory machined for the large OD, but a small OD cap was installed, they could spot face the replacement cap to match the flange OD relief cut of the block.

Or just use small OD flange bearings(which worked fine in 3 million 383’s).

 

[Nacho-RT74]

I know is not the thickness but the outer diameter. Just want to know the width of the machined surface… if somebody knows.

 

[Nacho-RT74]

Ok, my car is 6.5K miles from my actual home and I have to take decisions based on what I remember and with the info I’m getting. It has been LOOOOONG time since I build my engine. Mains needs to be cut from standard to .010. Long time ago I got a .002 set thinking a light polish will work… but not.

This is the .002 set and my friend who is trying to help compared the thrust against a 5/16 wrench.

Is this the large thrust kind or the small thrust?

 

[RemCharger]

Part number should be on the back

 

[Nacho-RT74]

The one on pic is as far I remember Sterling brand or something like that. Have to search for the PN

 

[PRHeads]

I was looking thru my old MP engine manual to see if it had the flange diameter listed.
I didn’t see it.
However, I did see something I don’t recall reading before.

It said that the B engine bearings changed in 1974.
They didn’t talk about the flange diameter, but mentioned the tab had been moved, and that early and late bearings weren’t interchangeable.
Whether or not the tabs have been moved or not I can’t say.

However, I do have a set of 80’s vintage Clevite ms876p here.
These are the “small flange” bearings.
The OD of the flange is 3.470”.

Edit- doing some on line digging, the only large flange B engine bearings I see are for like NOS F/M 4033M, which aren’t even in my 20 year old catalogs(supposedly fit 75-78 400).

The current “name brand” (Clevite, F/M, King) listings I found only show small flange OD sets.

It appears the aforementioned Clevite MB1348P were already gone by 2007, since that number is not in the catalog that year.

 

[Nacho-RT74]

The one on pic is as far I remember Sterling brand or something like that. Have to search for the PN

2321 cp-2

 

[Nacho-RT74]

Well... cap seems to be the large kind right? Machined surface is around 13 milimeters width

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