Holley 650 DP vs Edelbrock 600

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MOPARJ

MOPARJ

What can I upgrade now?
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Currently on my 318 with stock compression, XE268 cam, headers, relatively stock heads, stock converter and warmed up 904, I am running a Holley 650 DP vac secondary carb with electric choke. It runs well, with no stumbles or issues, but I think it is a bit lean. I currently am running #70 jets, up from 67s from the box settings. The plugs have a slight white shade, but not too bad to denote a major lean condition. I have been running this for 2 months now.

Should I continue to tweak on this, or pull it off and put the Edelbrock 600 vac sec back on? What has the better performance altogether? If I do swap, the Holley will go on my cuda's stock 340 with higher compression (although stock 340) amd of course, the better heads.

I am running 3.23 ratio gears on both cars.
 
Keep working the Holley. It will be better with the cam you have in there now. You would need to work the Eddy if you swapped it on there anyways.
 
Stick with the Holley. Are you running headers? What intake manifold? What kind of mufflers? What elevation are you at?
 
ramcharger said:
Stick with the Holley. Are you running headers? What intake manifold? What kind of mufflers? What elevation are you at?
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Running Hooker full length headers, Flowmaster 40 mufflers, 2.5" piping to the tail, h-pipe, Performer intake. with a 1" spacer, as I had to run that to clear the feed lines on the intake. I am right at or near sea level.
 
I would bump the primaries up to 74 and start there. Check your plugs, the center insulator should be a nice tan color (although there was a thread here in regards to how to read plugs, I've been doing this for almost thirty years and it works for me :)). Taking it to the strip is the ultimate dyno. Keep jetting up by twos (76, 78, 80 etc) until your MPH peaks, then drops off. Back off two jet sizes at this point. Now you can jet in increments of one for top MPH. You will most likely find that your optimum jetting will change in accordance to atmospheric conditions. The higher your state of tune (hp per ci), the touchier your carb settings will be. :)

Is this a 4150 series with a secondary metering block with jets or a 4160 series with a metering plate?
 
ramcharger said:
I would bump the primaries up to 74 and start there. Check your plugs, the center insulator should be a nice tan color (although there was a thread here in regards to how to read plugs, I've been doing this for almost thirty years and it works for me :)). Taking it to the strip is the ultimate dyno. Keep jetting up by twos (76, 78, 80 etc) until your MPH peaks, then drops off. Back off two jet sizes at this point. Now you can jet in increments of one for top MPH. You will most likely find that your optimum jetting will change in accordance to atmospheric conditions. The higher your state of tune (hp per ci), the touchier your carb settings will be. :)

Is this a 4150 series with a secondary metering block with jets or a 4160 series with a metering plate?
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4150 I believe, as I am changing the jets from the block up front.
 
A 4150 will have jets on both the primary side (front) and secondary side (rear). 4160 will only have jets in the front.
 
I'm with these guys. Keep on the Holley. Your right in the ball park. From here on out, it's just tweaks. The Edelbrock is a fine carb to use, but at this pont, to start all over again, re-jetting and tweaking, (Razzz berries) Stay with what ya got. Your doin fine.
 
Keep an eye on all the plugs and make sure the rear cyls (5,6,7 and 8 ) are not still running lean after bumping up the primaries. It's a good idea to maintain the jet stagger between the primaries and secondaries until you really get know your car/engine. Then you can take it to the next level. 8)
 
MOPARJ said:
The plugs have a slight white shade, but not too bad to denote a major lean condition. I have been running this for 2 months now.
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That sounds like you have the mixture about right. Because of the way the gas is formulated these days if you get the center ceramic to a tan color you are very rich.

FWIW, I am running a 670 Street Avenger on my 10.6:1 360 with an XE268H cam. The stock 65/68 jetting is just about perfect.
 
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