Carb recommendations
Thread Starter
Advanced
Joined: Jan 2011
Posts: 85
Likes: 0
Carb recommendations
Just curious about carb recommendations.
I currently have a Holley Street Avenger 670. I can not get rid of the off idle stumble no matter what jetting, nozzel, or other change I make. So its time for it to go.
My engine is 327 with RPM performer cam and manifold. World 64 cc heads. I forget the stall converter thats in it.
Any suggestions?
PG
I currently have a Holley Street Avenger 670. I can not get rid of the off idle stumble no matter what jetting, nozzel, or other change I make. So its time for it to go.
My engine is 327 with RPM performer cam and manifold. World 64 cc heads. I forget the stall converter thats in it.
Any suggestions?
PG
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Correctly set your timing, then get some help tuning the carb.
http://forums.corvetteforum.com/c3-t...long-post.html
The vast majority of carb problems...are timing problems
The carb is fine for your application - another carb isn't going to be any different.
http://forums.corvetteforum.com/c3-t...long-post.html
The vast majority of carb problems...are timing problems
The carb is fine for your application - another carb isn't going to be any different.
Last edited by billla; Aug 21, 2012 at 11:35 AM.
Instructor
Joined: Dec 2006
Posts: 167
Likes: 0
From: Oxnard/San Luis Obispo CA
I dont know how much of this you can change on the street avenger model, but off-idle stumble is likely to be accelerator pump related, and probably not a big enough pump cam. If you have a small pump cam, I would start there.
Pro
Joined: Apr 2009
Posts: 650
Likes: 1
Past history has shown that some SA Holleys have a bent accelerator pump arm right out of the box. Make sure the contact area of the arm is in the center of the pump diaphragm. Also make sure that when the arm is activated that there is no delay in the "squirt".
Good Luck.
Racer
Joined: Apr 2012
Posts: 465
Likes: 18
From: NorthEast
Correctly set your timing, then get some help tuning the carb.
http://forums.corvetteforum.com/c3-t...long-post.html
The vast majority of carb problems...are timing problems
The carb is fine for your application - another carb isn't going to be any different.
http://forums.corvetteforum.com/c3-t...long-post.html
The vast majority of carb problems...are timing problems
The carb is fine for your application - another carb isn't going to be any different.
Advanced
Joined: Jun 2006
Posts: 65
Likes: 0
From: SHADY SPRING WV
I had the same issue on a 350, 410hp engine. I tried every combo of nozzles, pump cams, and jets to no avail. Bought a 650 speed demon with mechanical secondaries and worked great right out of the box. Love those mech. secondaries!!!!
Thread Starter
Advanced
Joined: Jan 2011
Posts: 85
Likes: 0
What number are your primary jets and squirt nozzle?
primary 68/ seconday 76
Squirt nozzel is now 35
What color pump cam are you using?
orange screw is in second hole
accelerator pump arm is tight
I will work on the timing --again
thanks
PG
primary 68/ seconday 76
Squirt nozzel is now 35
What color pump cam are you using?
orange screw is in second hole
accelerator pump arm is tight
I will work on the timing --again
thanks
PG
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Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
I am almost sure I have seen a technical paper written by LARS on the set up of the Street Avenger series. I would shoot him an email and get a copy.
I can only offer my set up as a comparison for you. I have a 350 bored .060 so a 360 cid ,comp cam xe268h,60cc heads and auto trans. The carb is a Holley 600 with vac sec.
Primary jets are 65 (factory)
pump nozzle is a 35 (31 factory)
pump cam is white (pink from factory)
for me, using the Holley vac adv port did the trick with the adjustments above. I had to play with it a lot until I got it right. You may be one simple adjustment away from perfect!
I can only offer my set up as a comparison for you. I have a 350 bored .060 so a 360 cid ,comp cam xe268h,60cc heads and auto trans. The carb is a Holley 600 with vac sec.
Primary jets are 65 (factory)
pump nozzle is a 35 (31 factory)
pump cam is white (pink from factory)
for me, using the Holley vac adv port did the trick with the adjustments above. I had to play with it a lot until I got it right. You may be one simple adjustment away from perfect!
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
Was running a SA570 that gave me fits for a long time.Tried everything to get that carb to run right.Rebuilt it with all new parts,gaskets ,new metering block,and endless hrs of tuning.Carb always ran rich,idle mixture was all over the place.Finally gave up and installed a Summit 600 cfm carb.All issues are gone and I'm getting close to 20mpg with this carb.Old carb could only manage 13mpg..Here's the write up...http://forums.corvetteforum.com/c3-t...or-review.html
Le Mans Master
Joined: Aug 2010
Posts: 9,272
Likes: 17
Was running a SA570 that gave me fits for a long time.Tried everything to get that carb to run right.Rebuilt it with all new parts,gaskets ,new metering block,and endless hrs of tuning.Carb always ran rich,idle mixture was all over the place.Finally gave up and installed a Summit 600 cfm carb.All issues are gone and I'm getting close to 20mpg with this carb.Old carb could only manage 13mpg..Here's the write up...http://forums.corvetteforum.com/c3-t...or-review.html