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GMC V6 and V12 Engines Engine repair and rebuilding

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  #1  
Old February 9th, 2016, 07:10 PM
atomman atomman is offline
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Default Main bearing sets V-12

Are the main bearing sets for the V-12 the same as 2 sets of 351 V-6 main
bearings?
atomman
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  #2  
Old February 9th, 2016, 08:38 PM
bigblockv6 bigblockv6 is offline
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Default Re: Main bearing sets V-12

One of the biggest advantages of the 60 degree family of engines was parts interchangeability. The dimensions of the V12's bearing surfaces was the same as the V6 so it should be the same. If you have ant doubts on this matter contact ThunderV12.com.
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Old February 9th, 2016, 09:02 PM
atomman atomman is offline
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Default Re: Main bearing sets V-12

Thanks for the rapid reply. I just found a set of main bearings in VA at obsolete automotive wholesale Price was reasonable. They also have several rod bearing sets available in various sizes. Lots of valves and springs. This not an endorsement, but service was excellent.
Atomman
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Old February 10th, 2016, 01:09 PM
bobdylan bobdylan is offline
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Default Re: Main bearing sets V-12

I checked my manuals,crank shaft bores, 305 thru 478 are the same as 702. camshaft bearings #1-4 on 305 thru 478 will work on #4-7 on v12. Bob
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Old February 10th, 2016, 03:31 PM
bigblockv6 bigblockv6 is offline
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Default Re: Main bearing sets V-12

One thing to note, do not use main bearing sets for 1973-74 478 engines those have much larger diameter main journals.
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Old February 11th, 2016, 12:25 AM
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Cayoterun Cayoterun is offline
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Default Re: Main bearing sets V-12

Quote:
Originally Posted by bigblockv6 View Post
One thing to note, do not use main bearing sets for 1973-74 478 engines those have much larger diameter main journals.
Don't forget to be sure if your crankshaft has been turned down, if so how much to get over-size bearings to compensate.

I've kinda' faded back in the shadows on my tinker toys, so out of the loop pretty much on current sources----if any are left.
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I think I'll fix it myself, and pay the extra $500.
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Old February 11th, 2016, 03:32 AM
bobdylan bobdylan is offline
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Default Re: Main bearing sets V-12

Marvin. I was wondering where you have been. Anything new on the bus? Do you have a source for converting carbs from natural gas to L.P. Bob
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Old February 11th, 2016, 06:40 AM
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Default Re: Main bearing sets V-12

Hi, Bob: We've been dragging the TT around a good bit. Been, kinda', down in your country--- Extreme N/W Ark. lately. Going back for a spell this weekend. Hard to decide when it's time to turn our backs and walk away from the farm that I've spent about 65yrs on out here, but time marchs on. I'm thankful it will be in good, capable, young hands when we do, tho. He and family will be producing registered Hereford breeding stock.

Bus: My "can-do" seems to be getting slower than my "want-to", so it's still sitting.

NG-LP change: It used? to be a simple change when parts were still available.
I'll check tomorrow and write down the carb. names and numbers that I can't remember.
I know you'll need a regular/vaporizer to reduce your LP tank pressure down before going into the carb. You use a braided steel line from tank to regulator to carry tank pressure.

I'll drop you my regular E-mail by PM here, and get regular e-mail going, so we can get private commo or even phone going as it could get lengthy on this search, or could get lucky.
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I think I'll fix it myself, and pay the extra $500.
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