AMC 401 build-up, anybody?
#1401234
03/12/13 11:32 AM
03/12/13 11:32 AM
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Joined: Jan 2003
Posts: 9,876 Weddington, N.C.
Streetwize
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The last time I built an AMC 401 was close to 30 yrs ago but man it was an awesome piece.
My best bud is building a jeep CJ-7 and we're looking to do a 401 build-up along the following lines:
A good basic (broad torque 2500-5500) combo would be: 9.5:1 shortblock, +.030 bore, square decked, line honed, deck plate honed (if we can borrow/locate one for an AMC) Edelbrock performer RPM intake, port matched to heads Bowl ported Edelbrock heads, Serdi Valve job, install hardened locks (Edelbrock OEM is pretty skimpy) All oil passages in block and crank chamfered, the 'priority mains' mod would be good Deep sump pan with ported stock volume pump Hydraulic Flat tappet Cam in the 232/237 @.050 range and /.510-ish lift on 108 installed +4 at 104 ICL 1 3/4" x 3" Headers MSD 6AL or other good ignition Re-curved distributor with ~12-14 degrees initial and (limited to) 20-22 of centrifugal. good radiator Should make about 470-480hp with a bunch of mid range torque, peak power around 5200 redline 5800-6000
thoughts?
Last edited by Streetwize; 03/12/13 11:33 AM.
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Re: AMC 401 build-up, anybody?
[Re: Streetwize]
#1401237
03/12/13 12:37 PM
03/12/13 12:37 PM
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Joined: Dec 2006
Posts: 235 Tucson AZ.
RADAMX
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Tucson AZ.
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For a few more $$$ sb chevy rods and offset the crank . 421 cid More torque and better idle. The real problem is the cj springs .They are narrow and rap up real bad . Makes it a real chalenge to drive with a high torque engine. Either way the 401 can make a lot of power any way you build it so have fun
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Re: AMC 401 build-up, anybody?
[Re: Streetwize]
#1401238
03/12/13 12:53 PM
03/12/13 12:53 PM
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Joined: Jun 2004
Posts: 3,842 Ohio
john55
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I did that swap in 1980 to a '79 CJ5, what a torque monster that thing was everything was bolt in except exhaust....I built mine stock, used 1971 pistons for higher comp., ditched the Motorcrap carb for a Holley...
The Plymouth Win You Over Beat Goes On
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Re: AMC 401 build-up, anybody?
[Re: john55]
#1401241
03/12/13 03:37 PM
03/12/13 03:37 PM
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Joined: Jan 2003
Posts: 9,876 Weddington, N.C.
Streetwize
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We've actually talked about the 421" using the chevy rods, more cubes with an even lighter bobweight but not sure the additional cost is warranted for what we're going for.
i find that 232/237 @ .050 on 108 +4 is a great all-around high-torque grind for naturally Torquey moderate RPM motors in the 400-420 range with a stick....gives it a nice big block type powerband with enough intake duration to pull to ~6000 along with a nice 'count-em off' idle. With a hydraulic flat tappet on these small-ish port motors it's almost as much of a concern to go too small on the intake lobe duration than too big.
Should be fun little project, been a while since I worked on one. Ever notice how much an AMC resmembles a Buick? It's not coincidence if you read a bit into the history of Nash-Rambler/AMC.
Last edited by Streetwize; 03/12/13 03:42 PM.
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Re: AMC 401 build-up, anybody?
[Re: Streetwize]
#1401242
03/12/13 05:56 PM
03/12/13 05:56 PM
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Joined: Jun 2004
Posts: 3,842 Ohio
john55
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sounds like a cool project, more aftermarket choices nowadays than 33 years ago, wish we had those options back then, esp. w/AMC...
The Plymouth Win You Over Beat Goes On
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Re: AMC 401 build-up, anybody?
[Re: Streetwize]
#1401245
03/13/13 09:58 PM
03/13/13 09:58 PM
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Joined: Feb 2004
Posts: 6,257 acworth / N. georgia - south e...
cheapstreetdustr
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acworth / N. georgia - south e...
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growing up in jersey as a small kid..my neighbor was an amx guy...4spd...i used to watch him tune it up on weekends..dont know what engine it was..but it ran low tens back in 79. he used to drag race it at atco...
365" Iron J heads,,3480lbs best 1.39 60ft on SS springs.10.54,124 mph ...6.67 1/8th et.average 60fts 1.46 w/ small cam &.063 no2 pill tagged & insured [image][/image]
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Re: AMC 401 build-up, anybody?
[Re: 52savoy]
#1401249
03/15/13 02:06 PM
03/15/13 02:06 PM
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Joined: Jul 2010
Posts: 1,845 Tampa
DusterDave
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top fuel
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Tampa
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I hope your CJ guy has upgraded axles and driveshafts. The stock Dana 300 transfer case should handle it, tho.
Gone to the dark side with an LS3 powered '57 Chevy 210
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Re: AMC 401 build-up, anybody?
[Re: tsanchez]
#1401251
03/27/13 09:14 PM
03/27/13 09:14 PM
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Joined: Jan 2003
Posts: 9,876 Weddington, N.C.
Streetwize
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Met an awesome AMC guru up in West Virginia today named Barry Allen. We're gonna do a 401 with a crank offset ground to 3.8" to use a 6" SBC rod and a 4.195" Bore for about 420 cubes. Barry is awesome, so knowledgable and yet so down to earth about his vast knowledge. He built a 439" Indy AMC that Dyno's over 1000 hp, it was sitting on the stand. He aslso has some incredible port work done to several sets of AMC iron heads. OBTW, he had several other motors he was working his manic on, including the orange ones with the spark plugs going through the valve covers. VERY COOL guy!
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