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1967 Chevelle SS 396 L78 (Sold in 1970)
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Discussion Starter · #1 ·
I have a line on buying a nice 6223 crank (magged with polished journals) but the seller (who I believe is a knowledgeable Chevy engine guy), tells me from the factory back in the day it was not uncommon to find crank journals finished from the factory off by .001/.001. Not certain yet if that's "over" or "under" by .001.

Have any of you engine builders known this to be true? If so, is it an easy thing to get the correct thickness bearings for the journals that are off by .001?

Thanks!
 

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If needed there are bearings for that.
If clevite
MS-829P-1 or MS-829H-1
MS-829HX
 

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Discussion Starter · #3 · (Edited)
If needed there are bearings for that.
If clevite
MS-829P-1 or MS-829H-1
MS-829HX
Thanks for this information! Learned something else about engines today! I would think this is sort of rare right? Or, is it something fairly common 50 years ago? Any caveats going this route? Much appreciated!
 

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Thanks for this information! Learned something else about engines today! I would think this a sort of rare right? Or, is it something fairly common 50 years ago? Any caveats going this route? Much appreciated!
No idea? All std size oem BB chevy cranks I used didnt need any x or -1 bearings but I only used a handfull or so.
 

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Discussion Starter · #6 ·
I have found many factory cranks under by .001 It is not rare and there are bearings made to fit...
Well, this one is from the factory .001" oversize, so both the main & rod journals need .001" undersize bearings. I located some Clevite main bearings undersize by .001" but not much luck yet on the rod bearings. I want to know I have the bearings before I buy the crank, because the supply problem right now if brutal! I've been waiting on my 2,19" Milodon SS Valves since last October! Maybe August they tell me now. Any sources are welcome.
 

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1967 Chevelle SS 396 L78 (Sold in 1970)
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Discussion Starter · #7 ·
If needed there are bearings for that.
If clevite
MS-829P-1 or MS-829H-1
MS-829HX
Those are correct parts numbers for the main bearings, but how about rod bearings...any idea?
 

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I would ask him exactly what it measures. If he cant tell you then you probably don't want to buy it anyway. There is an almost .001" range for the sizes of both mains and rods. If he can tell you the exact size then you can decide what to do. And ask him how the thrust surface looks. Either that or figure on having it reground when you get it to make all of the sizes correct and correct the strokes while you are at it.

People dont realize how terrible factory machining really was / is. Thats why GM (and all of the others) have "select fit bearings to make up for factory differences. I have taken engines apart with three different size bearings in them from the factory.

To be honest with you unless you are getting the crank for $100 I just cant see buying it. You dont know if it came out of a 366 truck engine or a 427 etc. They are all balanced differently and can be a pain to rebalance.
 

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Everything BillK says in his above post is right on! See my private email to you, John.
 
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I would ask him exactly what it measures. If he cant tell you then you probably don't want to buy it anyway. There is an almost .001" range for the sizes of both mains and rods. If he can tell you the exact size then you can decide what to do. And ask him how the thrust surface looks. Either that or figure on having it reground when you get it to make all of the sizes correct and correct the strokes while you are at it.

People dont realize how terrible factory machining really was / is. Thats why GM (and all of the others) have "select fit bearings to make up for factory differences. I have taken engines apart with three different size bearings in them from the factory.

To be honest with you unless you are getting the crank for $100 I just cant see buying it. You dont know if it came out of a 366 truck engine or a 427 etc. They are all balanced differently and can be a pain to rebalance.
This explains the 6223 crank I bought that has had some oddball balancing done to it. It looks like they added weight but to hold the weight in they tacked it with a welder.
 
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