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Intake question |
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imacarfan2
AMC Addicted Joined: Jul/01/2007 Location: Northeastern MA Status: Offline Points: 971 |
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Posted: Apr/12/2021 at 3:30pm |
I'm trying to give the 390 in my 1970 Ambassador 4 door a little bit more zip. This car is a cruiser (has 2.87s in it), so I'm looking for torque more than upper RPM horsepower. I'm swapping in a small Summit cam (K8600) as I already have it. I'm also installing 72-up heads to lower the compression some. I plan on running free flow manifolds to duals and might try the Edelbrock AVS2 650 carb. Now here's the question:
I was planning on running a Performer intake, but found in my stash o' parts an R4b. Since I want down-low power, would I be better off staying with the Performer? With 390 cubes, does it not really matter much which one I go with? Just want the one that will perform the best (or better, at least) in this situation. |
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67 Ambo conv
68 AMX 68 Ambo 4 door 70 Ambo 4 door (2) 71 Hornets (1 SC/360) 73 Hornet 2 door 77 Matador coupe 77 Sportabout 78 Concord 2 door 81 Concord wagon |
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SC397
AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5476 |
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I am a R4B fan so I would go with that one.
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garland performce
AMC Apprentice Joined: Nov/19/2013 Location: sibley mo Status: Offline Points: 172 |
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R4B is bigger performance intake than the performer bigger runners and plenum
The performer intake will make more low end power and torque
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Sonic Silver
Supporter of TheAMCForum Joined: Nov/23/2011 Location: East Tennessee Status: Offline Points: 7949 |
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BassBoat
AMC Addicted Joined: Aug/29/2008 Status: Offline Points: 1718 |
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R4B. R4B is a real performance manifold and I have run it on 304 and 390. In my opinion the performer is for somebody upgrading from a 2 barrel. or one of those fugly spreadbore intakes.
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SC397
AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5476 |
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"Low end torque" is a relative term. If you want more low end torque than a AMC 390 or 401 then you might want to go to a Cummings Diesel... Seriously, I think people confuse low end torque with throttle response. One of the most low end torqu-y and throttle responsive engines that I ever built (as measured by my butt dyno) was in my Jeep truck. 401 with 8.3:1 compression ratio, R4B and a Carter AFB from a 343 that flows about 450cfm with Fre-Flow manifolds. I think the key to throttle response is a smaller carburetor.
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Sonic Silver
Supporter of TheAMCForum Joined: Nov/23/2011 Location: East Tennessee Status: Offline Points: 7949 |
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PHAT69AMX
AMC Addicted Joined: Jul/07/2007 Location: West Virginia Status: Offline Points: 5919 |
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Timing Advance Curve
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wrebelmachine
AMC Apprentice Joined: Aug/08/2019 Location: SW Missouri Status: Offline Points: 162 |
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I have had both love the R4B the performer is a decent off road intake. But I will throw this out there if you have a carb that is. Consider a Offenhauser Dual Port. More expensive but way more power than the performer especially down low and really everywhere over the performer. IMO.
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Sonic Silver
Supporter of TheAMCForum Joined: Nov/23/2011 Location: East Tennessee Status: Offline Points: 7949 |
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