08-28-2011, 04:45 PM | #1 |
Registered User
Join Date: Nov 2009
Location: Sonora California
Posts: 860
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350 blocks
I have a 73 350 motor, how can i tell if it's a 4 bolt or disired block? Right now it's too greasy to touch, so where and what do I look for? Fondling around dirty things is not my favorite.
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08-28-2011, 05:28 PM | #2 |
Registered User
Join Date: Feb 2010
Location: Fort Worth, TX
Posts: 727
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Re: 350 blocks
There should be a casting number on the back of the block, I believe there is one on the front by where the alternator mounts as well.
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08-28-2011, 05:37 PM | #3 | |
just can't cover up my redneck
Join Date: May 2004
Location: Columbus OH
Posts: 11,414
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Re: 350 blocks
As long as you are not intending to rev it's guts out, it doesn't really matter.
A 2 bolt block will stand up to the average performance build just fine. As long as the block is solid and not execssively worn, it's good to go.
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08-28-2011, 07:50 PM | #4 |
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Join Date: Jun 2011
Location: Armagh,PA
Posts: 138
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Re: 350 blocks
I would say just pull the oil pan and check the mains.
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08-30-2011, 07:47 PM | #5 |
Plays with trucks
Join Date: Sep 2003
Location: Asheville, NC
Posts: 433
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Re: 350 blocks
Check the casting number (passenger side back of the block). If it ends in 010 it's either a 4 bolt main or heavy duty 2 bolt main. Either is a good starting point if it's not been overbored by .060 yet.
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Gary My Dad's Old Truck 1985 |
08-30-2011, 07:52 PM | #6 |
resident wrencher
Join Date: Dec 2006
Location: ramona california
Posts: 720
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Re: 350 blocks
010 i beleive is the code for a 350 it wouldnt telly you main bolts or any thing there should be other castin marks and or stampings showing nickle content and main bolts and all that good stuff
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08-30-2011, 10:02 PM | #7 |
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Join Date: Jun 2008
Location: Lubbock, TX
Posts: 2,047
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Re: 350 blocks
Look for 010 and/or 020 under the timing chain cover, they're the better blocks, either 2 or 4 bolt. As long as it's a daily driver and not beat hard, a 2-bolt is fine. If you like driving it like you bought it at Harbor Freight, you best start with a good 4-bolt block. Gotta pull the pan, there are no single 350 castings from this time that tell if it's 2 or 4 bolt other than 400's.
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08-30-2011, 10:13 PM | #8 |
78K & 79C Jimmys
Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
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Re: 350 blocks
my 78 jimmy isn't (stock 305) but it's supposed to be "period correct" 350 with 4 bolt mains
this is what the back looks like and the front numbers you can usally blast back there with a pressure washer to see them
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John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350 |
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