318 main Bearing thrust diameter

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prorac1

prorac1

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After buying and installing main and rod bearings, I've discovered that there are two different sizes for the thrust Bearing diameter.

Our engine is a 1983, which has the larger diameter Bearing. I got this set of king bearings,

King SI-Series Main Bearings MB558SI

Which they don't say, but I believe is the earlier smaller diameter.

It dosent appear that it makes a big difference, but I figured I'd ask.

Thanks. Eric
 
If you look at the application it says 65 - 73 318 but doesn't specify the difference
 
brian6pac said:
If you look at the application it says 65 - 73 318 but doesn't specify the difference
Click to expand...

I noticed that also. I think either will work, one is just taller than the other.

I'm just looking for confirmation.

Thrust/crank end play is well within spec when measured after new bearings.
 
I don't know if it makes a big difference or not. but I would want the correct bearings. If yours requires a larger thrust surface and does not have it..........
 
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Here's a pic I found of the new thrust Bearing in place.

IMG_3472.PNG
 
I know. I'm just not looking forward to the possibility of buying another set of main bearings because I'm a dumbass. Lol
 
Of course on the other hand, if the engine holds together long enough to wear the thrust Bearing we would be greatful. Lol
 
If you had said "standard", I would have a different answer, but being an automatic there's limited need for the larger diameter thrust. will be fine for what your doing. Besides, that's what was used in the earlier model and it worked.
 
True. Manuals are a lot harder on them. And the wear in the factory thrust surface was very minimal. I think we will get by fine using it.


I just hate it when I learn things after I buy things. Lol
 
Had a co-worker put together a 383 brand "x" stroker together for his sons truck.
New crank, measured right where it should be.
The kings bearings supplied with the kit had .002" clearance on the rod bearings, and .005" on the main bearings.
He put clevelites in and tolerance was where it should be.
He just told me this to warn me to avoid the junk bearings.
 
King bearings are not junk bearings, I like their 3/4 groove mains. the smaller thrust worked fine from 1957-73, then they went a little bigger cuz bigger is better, and I think it was for the added safety crap of needing to step on the clutch when starting the engine
 
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