Author Topic: Please help me choose a Holley for a 340 with ported heads?  (Read 854 times)

Offline Ornamental

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I'm getting new heads built for me by Outrageously Vintage, Inc in Searmount, Maine.
This workshop have been extremely helpful and friendly, with excellent communication together with lots of pictures of the heads as the progress went on. The heads are ready for shipping now, and I'm very exited about getting more power in my currently anaemic '72 340.

Since they were building and porting the heads for me, I decided to ask them for a engine plan to fit the heads they would make.
I decided to just trust the shop with their choices, instead of referring to "my friends on the internet said to use so and so parts".
Still, I'm very grateful to CP and everyone else who came with their recommendations when I asked earlier.
 
The parts I'm recommended by them for my for my old '72 340 with the new ported heads, milled to a 10.25:1 compression is as follows:

DCC-4452992    238 Degree, .474 Lift Cam & Lifter Package    $179.95 (Mopar Performance Purple Cam)
ARP-144-4001    Head Stud Set (Recommended instead of Head Bolts)    $93.88
EDL-7803            Timing Chain and Gears    $59.95
MIL-16350          Water Pump    $53.99
Eddy Performer RPM Air-Gap

And here's what they recommended for carbs:
"Holley 750 Double Pumper Part #HLY-0-4779C    $433.95 if you would like a shiny finish Part #HLY-0-4779S $494.95
or
Holley 770 Vacuum Secondary Part #HLY-0-80770 $399.95

The vacuum secondary carb is going to be much better for low end torque, and there would be very little to no adjustments necessary.  The double pumper will give you about 10 more HP, but it will take quite a few adjustments to fine tune the low end performance."


I'm figuring that the low end torque of a double pumper won't be bad either, and most likely better than what I got now anyway. And 10 HP more won't hurt when I hit the gas for fun. Also, I think I could use the opportunity to learn a little about adjusting a Holley.

So what I'm asking, would I be crazy to choose the adjustment needing double pumper (DP) over the less adjustment needing vacuum secondary(VS)?

Also, I've read that the DP's needs re-adjustments over time more often than the VS, is this true, and if so is it really a hassle once you understand how to do it?
Panther Pink '72 Challenger Rallye.
Grey '70 Challenger R/T

-There are two kinds of pedestrians: The quick and the dead.

***Per Arne***




Offline 74 340 4speed

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Re: Please help me choose a Holley for a 340 with ported heads?
« Reply #1 on: May 16, 2008 - 11:09:59 PM »
750 Holley Street HP.  You can get it in manual or vacuum secondaries.  I'm running a vac. secondary 750 holley on my built 340.  It works very well, but I bet I am loosing some performance. 
Andy
1967 Camaro SS: 406 sbc 505 hp/506 ft lbs|4 speed|Posi|3.73s
1969 C/10  350|Turbo 350
1969 Dodge D300 318|4 speed|Dana|4.88s
1972Nova: 350|Turbo 350
1974 'Cuda: 340|4 speed|Dana 60|4.10s|posi
1999 Camaro SS: Auto|Longtube Headers|True Duals|TT2s
2013 Challenger R/T: 6 speed|Hurst with pistol grip|mopar performance exhaust|super track pak

Offline Chryco Psycho

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Re: Please help me choose a Holley for a 340 with ported heads?
« Reply #2 on: May 17, 2008 - 01:16:56 AM »
 :iagree:

Challenger - You`ll wish You Hadn`t

Offline Ornamental

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Re: Please help me choose a Holley for a 340 with ported heads?
« Reply #3 on: May 17, 2008 - 06:27:27 AM »
Vacuum secondaries it is!
Thanks again!

Er...  ...I just remembered, I'm told that electric chokes robs a little power, is it true?
Since I only drive the Chally in the summertime, I don't really need an electric choke, right?
Panther Pink '72 Challenger Rallye.
Grey '70 Challenger R/T

-There are two kinds of pedestrians: The quick and the dead.

***Per Arne***

Offline Chryco Psycho

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Re: Please help me choose a Holley for a 340 with ported heads?
« Reply #4 on: May 17, 2008 - 10:16:45 AM »
I agree , this is why I recommended the HP series Holley ,no choke

Challenger - You`ll wish You Hadn`t

Offline LAA66

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Re: Please help me choose a Holley for a 340 with ported heads?
« Reply #5 on: May 17, 2008 - 11:08:18 AM »
 My 650 double pumper has a manual choke but I don't use it as designed because it is harder to start with it. A few squirts on the throttle at start up and to keep it running do fine. I adjusted the cam on the choke so the idle can be manually adjusted in the cockpit during warm up but the butterflys and choke are not in play.  :2cents: