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4 bolt mains |
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Gench 
AMC Apprentice 
Joined: Oct/09/2021 Location: Boulder CO ish Status: Offline Points: 182 |
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 Topic: 4 bolt mainsPosted: Sep/09/2023 at 10:39am |
Old tread but I've been researching the same topic for years to validate what I believe to be a "Donohue block", in my 1970 Donohue. It's a 360 car, extremely well preserved. It's a Feb 1970 built car with build sheet stating "30 Mark Donahua"... spelled just as I typed, wrong. Sequence number is R020741. It has no displacement cast into the side of the block. Casting number is 3198951. Has a "2" stamp like the Penske example. Valve cover dates to Feb 12th build date. No idea what the webbing or main caps look like as I've never had it apart. That said, yesterday I was told to look at the front ear of the block for the service replacement info that is normally "stamped" into the block. Upon examination, mine isn't stamped but has "raised" text cast into the block ear... looks like "V 70 J" with the 7 and zero stacked vs next to each other. Is this the missing link? This car was a raffle car at the church of LDS. Romney was an executive at both LDS and AMC... do I have a unicorn? |
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17tamx
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Joined: Dec/23/2008 Location: Peoria, AZ Status: Offline Points: 1170 |
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Posted: Feb/01/2011 at 4:55pm |
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I have a late June 70 390 (306X25) in my 70 AMX and the rear casting number is the same as the 71 401. The block has the blank CID spots on both sides and the thicker webbing. When I pulled the motor apart and the seals and gaskets were factory AMC part numbered items including the head gaskets.
Anyone else out there with a late June or early July 70 390 engine that also didn't have the 390 CID cast into the side of the block?
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Kirk P. Fletcher
70 AMX BBG w/Shadow 390 4sp 71 SC360 Wild Plum Ram Air 4sp 67 Rogue Convert 343 4sp 66 Rogue Hardtop 290 Auto 66 440 Convert 232 Auto |
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Rebel Machine
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Joined: Jul/03/2007 Location: Western Il Status: Offline Points: 5122 |
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Posted: Jan/30/2011 at 8:21pm |
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Does yours have the 401 on the side?
-Steve-
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390spirit
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Joined: Jun/28/2008 Location: U.S.A. Status: Offline Points: 1849 |
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Posted: Jan/30/2011 at 5:24pm |
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i just checked my 401 block and its the same as yours Steve 3198951 and i believe its a 1974 401
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390spirit
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Posted: Jan/30/2011 at 5:20pm |
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3195529 on my 70 390 block
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Rebel Machine
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Posted: Jan/30/2011 at 4:22pm |
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Snapped a couple of pics of the service block I have. Casting number is 3198951. According to The Red, White and Blue Book (by Frank Swygert) it is a '71-'78 401. There is also a casting number 448 7213 that is supposed to be a '70 390 service block. The R/W/B book doesn't list it.
Is this casting number a service block or did someone simply grind down the 401 on the side?
-Steve-
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SuperStockAMX
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Joined: Dec/29/2009 Location: Anthem, Arizona Status: Offline Points: 237 |
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Posted: Jan/25/2011 at 10:49pm |
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My guess is you have a very early '70 block as your probably confident it is not a '68-'69 block. Just goes to show there is nothing hard and true with mass production.
Oil pan is not a problem with Pro-Gram caps. As I said, only the center 3 are 4-bolt. I ran all 5 as I wanted the superior metal across the board. But it is not necessary.
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crossramrambler
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Joined: Dec/13/2008 Location: Reno,Nv Status: Offline Points: 494 |
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Posted: Jan/25/2011 at 10:38pm |
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Here is a picture of my 70 390 with pro gram 4 bolt mains. It does not have the wide webbing like the 401 block......Jim.
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SKeown
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Posted: Jan/25/2011 at 7:38pm |
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The front & rear caps are still two bolt, only the three center are four bolt.
SKeown
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poormansMACHINE
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Posted: Jan/25/2011 at 7:22pm |
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The blocks aren't machined flat where the additional bolts locate so add that to shop work.
Pan shouldn't interfere since the caps aren't that tall. |
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