4 bolt mains
Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=26116
Printed Date: Apr/19/2024 at 6:03am
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com
Topic: 4 bolt mains
Posted By: WVAMX
Subject: 4 bolt mains
Date Posted: Jan/22/2011 at 7:49pm
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I have read articles that a Mark Donohue Javelin had 4 bolt mains in a 360. I have seen several 360's torn down but non had 4 bolt mains. Did they or didn't they? If they did then that should be a good indicator that a Javelin SST is a Donohue. ------------- 70 AMX, 70 Mark Donohue, 74 Javelin |
Replies:
Posted By: 69 ambassador 390
Date Posted: Jan/22/2011 at 8:06pm
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The race ones had the 4 bolts and a trans am block. The stock ones did not. There may have been a few released to the public for homologation reasons but I have never seen one in a consumer vehicle. ------------- Steve Brown Algonac, Mi. 69 Ambassador sst 390 84 Grand Wagoneer 69 Cougar XR7 65 Fairlaine 500XL 79 F-350 Super Camper Special |
Posted By: RSX 401
Date Posted: Jan/22/2011 at 11:10pm
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I've only seen one AMC V8 4 bolt main and it came out of a TA Javelin. ------------- I'll follow these lines a little ways more, Until I can find what I'm looking for. With the pedal to the metal, I'm gaining my speed. Riding down low in my AMC..... |
Posted By: bulletpruf
Date Posted: Jan/23/2011 at 6:44am
 ------------- Please check out my YouTube channel for vintage car and truck shenanigans! https://www.youtube.com/@THEBULLETPROOFGARAGE |
Posted By: amc37643
Date Posted: Jan/23/2011 at 7:32am
| Bulletpruf is this block standard in web thickness at the bottom for use of these 4 bolt mains or thicker? reason for asking some say using 4 bolt mains weakens the standard blocks. |
Posted By: prostreetamx
Date Posted: Jan/23/2011 at 8:36am
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I've only seen 401's with the wide flange that could be drilled for 4 bolt mains. There was a 4 bolt provision service block offered at one time, but I have never seen it myself. My 360 Donohue did not have this block. ------------- Richard Payne Las Vegas,NV 72 5.7 Hemi Javelin 77 Prostreet 401/727 AMX,  [/URL]
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Posted By: bulletpruf
Date Posted: Jan/23/2011 at 8:54am
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NASCAR Penske engine. 357 cu in.
     ------------- Please check out my YouTube channel for vintage car and truck shenanigans! https://www.youtube.com/@THEBULLETPROOFGARAGE |
Posted By: amc37643
Date Posted: Jan/23/2011 at 8:56am
| Was the 401 block a standard 401 (run of the mill type as would have been in full size JEEP) or something different? |
Posted By: bulletpruf
Date Posted: Jan/23/2011 at 9:20am
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Believe it was a service replacement block w/no CI cast into it. All cylinders sleeved; presumably to bring CI down for NASCAR. Crank is a destroked 401 crank full of heavy metal. ------------- Please check out my YouTube channel for vintage car and truck shenanigans! https://www.youtube.com/@THEBULLETPROOFGARAGE |
Posted By: Rebel Machine
Date Posted: Jan/23/2011 at 9:50am
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Wow, interesting piece of racing history you have there. Looks like a few oiling and cooling modifications were made. Also looks like rod 3 or 4 let go.
Is there a casting number on the block?
-Steve-
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Posted By: bulletpruf
Date Posted: Jan/23/2011 at 10:21am
Not mine. Belongs to a friend.
Block was stamped RP 357 011 (Roger Penske, 357", 11th engine built) or something like that. Built by Traco.
Scott
------------- Please check out my YouTube channel for vintage car and truck shenanigans! https://www.youtube.com/@THEBULLETPROOFGARAGE |
Rebel Machine wrote:Posted By: Rebel Machine
Date Posted: Jan/23/2011 at 2:36pm
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I was thinking of the casting number usually located at the back of the block on the driver's side.
-Steve-
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Posted By: bulletpruf
Date Posted: Jan/23/2011 at 3:25pm
Not sure what the casting # is; he never sent me a picture of that.
Scott ------------- Please check out my YouTube channel for vintage car and truck shenanigans! https://www.youtube.com/@THEBULLETPROOFGARAGE |
Posted By: SuperStockAMX
Date Posted: Jan/25/2011 at 5:11pm
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The 1970 390 & 401's have the wide webbing which will accommodate the 4-bolt main conversion. There is also a service block sometimes referred to as the T/A block, sometimes referred to as a Mark Donohue block which was machined to 360 bore with the wide main cap webbing. The dealer (or factory) could use this as necessary; 360 - 390 - 401. Pro-Gram and Milidon produce after market 4-bolt main caps. ------------- 1970 AMC AMX NHRA SS/H Class MACH Development 4300 Autolite equiped 390, Jerico 4-speed w/ Advanced Clutch |
Posted By: amc37643
Date Posted: Jan/25/2011 at 6:31pm
| Anyone familiar with the # that would be on the block to designate a block with the wide webbing that would accept machine work for 4 bolt mains & its location on the block? someone on a earlier post said something about it being on the rear of the block,just trying to save disassembly to check cant remember a tag on V.C.on this 401 supposibly from a AMBASSADOR |
Posted By: SuperStockAMX
Date Posted: Jan/25/2011 at 6:55pm
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If it is a 1970 390 or 401 (any year), it has the wide webbing. The 360 service block is the only exception. It will not have an engine size cast into the side of the block (behind the motor mount). There may be some exceptions with the service block but your question is more geared to the 401 you have. I have the Pro-Gram mains and bought all 5. You can elect to go with the center three if you prefer. ------------- 1970 AMC AMX NHRA SS/H Class MACH Development 4300 Autolite equiped 390, Jerico 4-speed w/ Advanced Clutch |
Posted By: amc37643
Date Posted: Jan/25/2011 at 7:15pm
| Are there any oil pan conflicts on the rear of the engine if all 5 are installed?,any other mach.work other than drill & tap for extra bolts & line bore block with new caps required? |
Posted By: poormansMACHINE
Date 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. |
Posted By: SKeown
Date 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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Posted By: crossramrambler
Date Posted: Jan/25/2011 at 10:38pm
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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Posted By: SuperStockAMX
Date 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. ------------- 1970 AMC AMX NHRA SS/H Class MACH Development 4300 Autolite equiped 390, Jerico 4-speed w/ Advanced Clutch |
Posted By: Rebel Machine
Date 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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Posted By: 390spirit
Date Posted: Jan/30/2011 at 5:20pm
| 3195529 on my 70 390 block |
Posted By: 390spirit
Date Posted: Jan/30/2011 at 5:24pm
| i just checked my 401 block and its the same as yours Steve 3198951 and i believe its a 1974 401 |
Posted By: Rebel Machine
Date Posted: Jan/30/2011 at 8:21pm
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Does yours have the 401 on the side?
-Steve-
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Posted By: 17tamx
Date 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? ------------- 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 |
Posted By: Gench
Date Posted: 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? |