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1984 Grand Wagoneer w/401 |
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devildog80
AMC Apprentice Joined: Jul/29/2022 Location: Apache Junction Status: Offline Points: 143 |
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Hey 401 Experts,
I have been trying to figure out what year my engine is, as the tag on valve cover is missing, and that is the only way I know to check. Besides the casting of "401" on the block which only tells me it's a 401, are there other ways to know approximate year the engine could be? I have the rebuild paperwork from PO, but nothing to indicate what year or where it came from.
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devildog80
AMC Apprentice Joined: Jul/29/2022 Location: Apache Junction Status: Offline Points: 143 |
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Finding threads online
Guess I did not have the search worded correctly before :/ https://theamcforum.com/forum/amc-block-casting-dates_topic86791.html I need to check some of these numbers - The only real way is to take off the intake and look at the date code cast on the block. But there are other clues that can help. First is to look at the casting number drivers side top rear of the block. Should be: 3195528 ..... 401 ..... 72-76 3198951 ..... 401 ..... 71-78 3220411 ..... 401 ..... 75-78 3414725 ..... 401 ..... 72-74 4488874 ..... 401 ..... 71-76 Next would be the taking off a valve cover and see the head part # and rockers, single or bridged. 401 71 Single 319 6291 401 71 Single 321 2993 812 0126 Service replacement for 71-72 Heads 401 72 Single 321 3948 401 73 Single 321 6090 401 74 Bridged 322 0502 The vibration damper in71 and early 72 is 3 bolt and all later are 4 bolt. |
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19611 |
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Forget about those carb calculators. They are good to put you in the ball park, but are mainly geared toward all out racing. A SMALLER carb is actually better for lower rpm torque. That's why the International version of the 401 only came with a two barrel. AMC never made one for their own use with a two barrel carb. A 500 cfm (square bore) 4V is a good carb for towing/highway use. It will obviously run out of capacity much over 4000 rpm (maybe up to 5000...) but you don't run that high very often, if at all. The Quadrajet with two small primaries and larger secondaries is a good carb, but for your stated use a square bore may be better. That and a Dual Plane intake.
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Frank Swygert
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devildog80
AMC Apprentice Joined: Jul/29/2022 Location: Apache Junction Status: Offline Points: 143 |
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So no issue to be had with a cast OEM 4 bbl intake?
I am more of a self taught wrench turner grew up on a farm/ranch, and not so much a true blue gear head, to figure out dual planes, square bores vs ???.....most days I forgot most of what I thought I knew! What I do know, if I use the OEM 4 bbl intake with Q-jet carb....pretty much OEM on some makes back in the day, I might get 12-14 mpg with a 40 mph tailwind down hill in neutral. I can live with that, and even less mpg if it is! If I start ramping up the budget to dump $1500-3000 for smoother, cleaner, brighter, for what 13-15 mpg? The life of me driving this truck is not worth the layout to do that, as I might only spend that much in actual fuel cost, for my intended use. I like the OEM look and feel of how these old trucks drive as designed, and love to tinker and keep up with them when needed. Not into the shiney stuff or modernizing them to try and imitate the newer stuff most of us drive. Ultimate goal is to have it as close to how it was, reliable and safe, to get us out there and back home without incident. Did I go waaayyyy out there......without understanding what you said? Sorry if I did :/
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6762 |
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You will likely find a square bore 4 barrel factory intake easier and it will open up more choices of modern carburetors that handle ethanol fuel better.
Have to disagree with Frank, AMC or Jeep never put less then a 600 CFM carburetor on a 401. For a truck, this would be a better choice with the factory camshaft. Read some of the Jeep Forums and you will find most are in the 600 to 650 range for their vehicles. |
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Cricket
AMC Addicted Joined: Jul/06/2015 Location: Milton, FL. Status: Offline Points: 736 |
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If you have a factory 4 barrel intake for a later 401, it would have the Motorcraft spreadbore pattern, but it is different than the quadrajet spreadbore pattern(which AMC nor Jeep ever used), so you would need some sort of adapter. A quadrajet will not bolt directly on, but you may know this by now, just wanted to throw that out there. I watched someone try to bolt a quadrajet on an intake where a 4350 carb came off, and they could not figur out why it would not even open the primary throttle. If you want to run a quadrajet, find an early square bore intake, and buy an adapter to put it on, as I have never seen a Motorcraft to quadrajet adapter. Someone might speak up and prove me wrong.
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6762 |
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There was an adapter, but Ford and Jeep people do this quite often still:
"Edelbrock aluminum adapter, turned upside down (originally intended to put a squarebore on a factory QJ manifold). If you use this unit: It took some dremelling on the secondary openings to where the secondary throttle plates wouldn't bind. You have to be careful about gaskets and how you center the carb, because the adapter just barely covers all the vacuum ports and channels on the bottom of the carburetor."
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devildog80
AMC Apprentice Joined: Jul/29/2022 Location: Apache Junction Status: Offline Points: 143 |
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If i ran my rpm's up to 6000, the calculator was showing about a 650 cfm, which is right in line with the Q-jet. The MC2150 I currently have I think is around 450-500 cfm. I will put a few 100 miles on it, and see if changes will be needed, before doing anything. Thanks
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devildog80
AMC Apprentice Joined: Jul/29/2022 Location: Apache Junction Status: Offline Points: 143 |
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The current 2 bbl OEM intake I have, believe came off the 360 that was in the truck from factory. What the 4 bbl intake that came as extra parts.....no clue. Would need to get some casting numbers and see! And no, I did not know the Q-jet would not bolt on, as there is much I do not know, and why I am here asking questions. I am not a racer, or super dedicated enthusiast towards any make or model, and only want my vehicles to perform best as designed. Three years ago I had an opportunity to buy my first Jeep, '81 CJ5 - 258 - 4 spd, and takes me back to my childhood when we had to have 4x4 pick ups to get farm work done. Fell in love with the little thing now, then in April was lucky to get the '84 Grand Wagoneer dirt cheap, so I guess I have now the official Jeep virus. Heard from many on the CJ Forum the 401 is like a Holy Grail engine, IF you can find one, and 2000 miles on a fresh rebuild even better. So, as I know little about this truck and/or its components, I am here to learn all I can about what I have, but I do not have the budget or desire to upgrade with bling and sparkle, as I cherish the basic function of what these trucks can do, and not so much what they look like. I love a truck that can be driven 10 or 10,000 miles, and reliable to get me there and back. I have good mechanical aptitude, want to do as much of the work needed myself, as it is my time when I am wrenching and driving what I work on. Knowing what it needs or not, as long as it is driving, is fun for me and my family to get in and go. In a nut shell, please assume I know nothing of what fits this or that, but that I want to work with OEM specs of what will work or won't. I really appreciate the input from everyone, and apologize for any frustrations to those who know soooooo much more than I :/
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devildog80
AMC Apprentice Joined: Jul/29/2022 Location: Apache Junction Status: Offline Points: 143 |
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IF I find the MC2150 is not enough, or not right for my driving wants, I will verify the 4 bbl intake "fit to carb" and have it all working before pulling what I have now. Thanks
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