First, going larger may have been a mistake.

Second, regardless if it was a mistake or not, you can tune the carb.  My guess would be the current setup is too rich.  Get the Edelbrock tuning kit and lean it out two steps and see if power improves. 

Alright, thanks guys. But
And there's a but.......everyone focussed on the Edel. Nothing was mentioned on the Holley. It was a 600 DP. 68Prim 73Sec.
The richness 'smelled' greater than this current Edel.  Yet, get up and go performance, and pretty much all lower end performance was noticeably greater.


Now as for size (assuming all tuning equal) has been pretty much debunked in Bench Engine dyno testing (aware in practical things would change to some degree).
Check This Out!!!  http://www.superchevy.com/how-to/148-0403-seven-holley-carbs-test/

Now from my experience on the 351W moded equally to this 302, only for a 351W (had a milder cam actually) I went from a Holley 750DP which made the car a monster!  To a recommended 650DP by a pro engine race shop. .........INSTANTLY noticed and felt and and and a DECENT power drop!
To experimented with a Holley 800DP.....and I can comfortably say the 750 All around, hands down performed the best!  It was like the perfect everything.  The 800 lacked in low end performance, but really shines in higher Rpms.


So why such a variance from my Out of the box 600 Holley DP and the 650 Edel?

This may help some

Edelbrock Carburetor Tuning

John Ha wrote:

This may help some

Edelbrock Carburetor Tuning

Only issue is.............."IF you ain't an engineer.....it's hard to follow what chew dun".
Give us a "blow-by-blow" of where you started and where you ended up and what you done (and what issue you fixed) Please.
6sal6
 

6sally6 wrote:

Only issue is.............."IF you ain't an engineer.....it's hard to follow what chew dun".
Give us a "blow-by-blow" of where you started and where you ended up and what you done (and what issue you fixed) Please.
6sal6
 

What was fixed is the chart in the Edelbrcck instructions.  The gradations in tuning it provides were pretty coarse.  My chart provides a much finer tuning guide.  The great thing is that you don't have to be an engineer to use it since all the math is already done.  :-)

The rod, which fits in the jet, has 2 diameters and positions: cruise and power.  In either "cruise" or "power", the rod occupies part of the cross-sectional area of the jet, allowing more or less fuel through, depending on whether the large diameter of the rod (cruise) is in the jet or the smaller diameter of the rod (power) is in the jet.  All I've done is combine the different rod dimensions with the different jet dimensions, calculated the cross-sectional jet areas available for each rod position (cruise and power) and sorted them.  

For example, let's say you're running the factory baseline of a 1459 rod and a .098 jet.  if you're lean in "power" but OK in "cruise", you find your rod and jet combination on the "sorted by power area, cruise area" table, then select the next jet and/or rod that has a larger power area but try to keep the same cruise area.  A 1449 rod with a 0.95 jet gets you there.  Or you can use the same 1459 rod with a .01 jet and get a little richer in both cruise and power.



Hope this helps  some.  If not, ask away and I'll try to explain better or answer your questions  :-)

Last edited by John Ha (8/20/2020 5:35 AM)

6sally6 wrote:

Now THAT makes things a lot more better-da-kind Bro!!
UR right.....your explanation IS ez'er to understand.
What would be the indication of "lean in power but OK in cruise"? How does the car act under this condition?
Thanx in advance  6sally6

I used the guidance in the carb manual, reading the spark plugs and my butt dyno (I had a 1400 series but the process should be about the same). The manual guidance states:
.
CRUISE MODE   If there are any surge or flat spot conditions in the steady speed cruises or light accelerations, a lean condition probably exists. Consult the Calibration Reference Chart and change to 1 stage rich in the Cruise Mode. If it gets better, but not completely fixed, keep going in the rich direction. The Calibration Reference Chart will give you Rod and Jet combinations that are directionally correct or you may choose your own.If the light throttle is satisfactory, trying going 1 stage lean in the Cruise Mode. If there are still no problems with surge or other indications of lean metering, do not hesitate to go to 2 stages lean in the Cruise Mode. A lean Cruise Mode has advantages in fuel economy and keeping the plugs clean. Keep going until you begin to notice driveability problems and then back up 1 stage.
.
POWER MODE   Accelerations at part-throttle with low manifold vacuum (less than about 5" Hg on a vacuum gauge) are metered by the Power Mode. Avoid calibrating this portion of the engine’s operating range too lean as spark knock (detonation) and piston/valve burning can occur. If this mode has any lean driveability symptoms (surge or flat spots), it is too lean and should be re-calibrated at least 1 stage richer.
.
I looked at the current owner's manual for these carbs and found that the chart I did does not cover the possible combinations of rods and jets for the AVS series so I'm working on one of those.  Hopefully I'll get get it done today. 

Last edited by John Ha (8/21/2020 6:47 AM)