Edelbrock AVS2 question

[ChargerChad]

I’ve got a ‘71 Charger, bone stock 383 with 59k miles. Stock Holley had seen better decades so I hit the easy button and changed to a 650 cfm AVS-2. This was in conjunction with changing the old points ignition to a two-wire electronic distributor with a new coil. Wow, what a difference! I did have a slight ping under a load that went away when the secondaries opened. Played with the timing a bit, no change, so I jetted up two steps to a 404 main and problem solved, along with a noticeable improvement in acceleration. My question is should I step up in the secondary jets as well? If I was running a Holley I would have, but not sure if I should with the Edelbrock. I am suspicious now as to whether I am carb’d too small… I love this carb and they do make it in 800cfm…

 

[R413]

Lean will ping, the secondaries opened, more fuel, ping gone. Also ping will go away with higher RPM.

the engine bone stock 383 so an 800 is too big IMO.

 

[RJRENTON]

Lean will ping, the secondaries opened, more fuel, ping gone. Also ping will go away with higher RPM.

the engine bone stock 383 so an 800 is too big IMO.

I agree as well, stay with the Edelbrock 650 CFM AVS-2. Consider increasng the secondary jets by the same percentage as you increased the primary jets....or did you just change the primary step up rods? Slightly rich at WOT is better than too lean. I have an origional Holley R-4668 which is rated at 750 CFM if interested. PM me....
BOB RENTON

 

[ruffcut]

I've run Edelbrock carbs for decades and have 2 750 CFM on my 500 inch max wedge and 1 800 AVS2 on my 512 inch in the Roadrunner.
Have had numerous other Edelbrock carbs on other Dodge trucks, etc. The 650 you have is the right choice for a 383.
That being said, you're on the right track by doing some tuning to get it dialed in. A 650 will give you a better signal than an 800 CFM on the 383 and result in better performance. especially on bottom end, for the street. My 2 cents. ruffcut

 

[SlinktRR]

I had a 650 AVS on a 71 383 HP it worked fine just gives up a bit at high rpm. Good street carb. If you look at the 650 and the 800 side by side they are different in that the 650 has tiny primaries and bigger secondaries while the 800 all 4 are equal size. The 650 is a very responsive carb with this configuration but not a high performance unit.

If you just changed the jet from stock .101 to .104 with the same 70x37 metering rod you are in the top right corner of the calibration chart at #17 (look in the owners manual for the reference chart) and also two stage rich for both cruise and power. Thus you will want to jet the secondary two stage rich, which turns out to be the same .101 jet you just took out of the primary. Just swap those in and see how your power is. Edelbrocks are really easy to adjust which I think makes them great carbs just not perfect for every application.

I went to 4150 holley after the 383 because when running the 800 AVS on a 499 stroker I was always jetted off the charts, literally. I ended up using .119 jets which you have to special order. Got 13 mpg though on the 499 which I thought was pretty good. The 650 on the 383 and 3.23 gears would net me 20mpg.

 

[ChargerChad]

I agree as well, stay with the Edelbrock 650 CFM AVS-2. Consider increasng the secondary jets by the same percentage as you increased the primary jets....or did you just change the primary step up rods? Slightly rich at WOT is better than too lean. I have an origional Holley R-4668 which is rated at 750 CFM if interested. PM me....
BOB RENTON

Thanks for all the advice, guys.

I went 2 stages rich on the primaries which, according to Edelbrock's tuning chart, kept the stock metering rods in bigger jets. I'll do a corresponding increase in the secondaries as well and then see if I can push in a couple more degrees of advance. This is my first 383 car and I'm really getting to be a fan of this engine. It responds immediately to tuning changes and really lets you know when you've done something right.

 

[ChargerChad]

I had a 650 AVS on a 71 383 HP it worked fine just gives up a bit at high rpm. Good street carb. If you look at the 650 and the 800 side by side they are different in that the 650 has tiny primaries and bigger secondaries while the 800 all 4 are equal size. The 650 is a very responsive carb with this configuration but not a high performance unit.

If you just changed the jet from stock .101 to .104 with the same 70x37 metering rod you are in the top right corner of the calibration chart at #17 (look in the owners manual for the reference chart) and also two stage rich for both cruise and power. Thus you will want to jet the secondary two stage rich, which turns out to be the same .101 jet you just took out of the primary. Just swap those in and see how your power is. Edelbrocks are really easy to adjust which I think makes them great carbs just not perfect for every application.

I went to 4150 holley after the 383 because when running the 800 AVS on a 499 stroker I was always jetted off the charts, literally. I ended up using .119 jets which you have to special order. Got 13 mpg though on the 499 which I thought was pretty good. The 650 on the 383 and 3.23 gears would net me 20mpg.

That's good info. That's another reason I like the Edelbrock is the ease of tuning with the available literature. I used the tuning chart you mentioned but I also found a Summit tuning chart for the 1906 that suggests more drastic changes.
I am going to do a rebuild on the engine this winter, not anything wild but the plan is to go .030 over and get the compression up to just over 10:1 with aluminum heads and a mild-ish cam. This will probably mandate the 800. This will always be a street car for cruising with my wife and kids and will rarely if ever see over 5000 rpm so the Edelbrock should fit the bill. If not, I'll be back to Holley.

 

[Geoff 2]

There is an old saying that most people take no notice of, but you are sensible & taking note: better to under-carburate than over-carburate.

 

[topside]

Interesting. I went 2 steps leaner on the primary rods on the 650 AVS2 I put on my '68 car - a basically stock RR 383.
FWIW, I'm at 2600 ft elevation, weather is often like about 3000 ft DA.
Great carb, very responsive.