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Which size main and rod bearings for a 427?

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Old 08-16-2004, 04:57 PM
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Default Which size main and rod bearings for a 427?

My shortblock is about ready to come together. I just need to order the rod and main bearings but do not know what size to get. I have a Callies 4.000 crank and Eagle 6.125 rods. Could someone help me out?
Old 08-16-2004, 05:36 PM
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Same as stock.
Ls1 specific mains and good old fashion small block chevy rods.


Originally Posted by 11 Bravo
My shortblock is about ready to come together. I just need to order the rod and main bearings but do not know what size to get. I have a Callies 4.000 crank and Eagle 6.125 rods. Could someone help me out?
Old 08-16-2004, 05:52 PM
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Yes, but there are different ones. For instance, there is the Federal Mogul main bearing, 3/4 groove with different #'s: STD, +1, +10 and 1X. Same with the rod bearings and I don't know which ones to order.
Old 08-16-2004, 05:54 PM
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You can't know unless you are checking the bearing clearance! Only the engine builder or assembler knows that. You can't know without measuring everything.
Old 08-16-2004, 06:42 PM
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I am going to build it. How do I check bearing clearance without bearings?
Old 08-16-2004, 07:39 PM
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u have the dia of the mains - the diameter of the crank = X

bearing size is Y thickness .... X - Y is clearance... theoretically...


but to be honest... if you have to ask this question you should not be building this 427 unless you have some help.
Old 08-16-2004, 07:51 PM
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2.100" for the rods
Old 08-16-2004, 07:58 PM
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C'mon, don't be discouraging to him. Not all of us have built our own motors. Yet. Ya gotta start somewhere.

You might try getting a set of standard bearings, and measuring the clearances with those. You may have to end up getting a different size, depending on how tight you want the clearance (which impacts oil pressure) - so yes, it may cost more money. But you're learning, right?
Old 08-16-2004, 08:12 PM
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Well, I'm no pro, but I do have 4 sbc and 1 455 Olds rebuilds in my book, and used rebuild kits that already came with bearings, so I did not have to figure that out. All turned out fine lol. I think I can get the job done. I know how to build a motor, just need help figuring on what bearings to order. Nothing more.
Old 08-16-2004, 08:32 PM
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Order the standard bearings Mike and use plasti-gauge to check the clearances. As long as the crank and rods are new, you should be at .0015 to .0025 clearance. If you are less than .0015, you can have the crank journals polished a bit to get another .0005 - .001 clearance. If you are more than .0025, then step up to a +1 part number.
Old 08-17-2004, 04:02 AM
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Got it. Thanks, Todd!
Old 08-17-2004, 04:18 AM
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No problem! Just remember to check the clearances with no lube on the crank journals.




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