When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Been trying to get this one running with a 3rd (or 4th) hand Holley setup and finally gave up and bought a new Edelbrock 500 AVS2. It Lives! I've always been an Edelbrock guy and feel comfortable with them. The Holley was my 1st, and a tired puppy at that. I found a few threads where members such as Wankel=Awesome and Qingdoa recommended them for fuel slosh control vs the Holleys, so OKay, let's try it.
Well, I can see why Racing Beat uses Holleys. They fit. The fuel inlet, linkage, choke, all just fit there. The Edelbrock is a little more difficult, but I got it. Okay, pics...
You need a 1" spacer to lift the choke above the thermostat.
The choke clears but the throttle shaft still rubs lightly. I trimmed the rubber rad hose slightly, will be replacing it soon anyway.
The RB throttle linkage plate worked fine, except that the Edelbrock's linkage sticks out over an inch further towards the firewall than the Holley's did. I used some 1/4" hardware and some of the RB Holley bits to line the cable up better, so it won't bind or wear.
I was going to mount the FPR here on the firewall like most people do, but it's a hot area right above the header.
So I kept all the fuel lines over the engine, on the cooler side of the carb. I brazed 2 nuts to the RB Throttle plate, tapped a 3rd hole, and mounted the FPR there. Not pretty, but it works very well.
FPR is a return style, plumbed into the stock return line. I kept the stock charcoal canister but moved it onto the firewall for more space. With the drilling of one extra hole in the bracket, I was able to mount it onto the cold-start fluid mounting holes. Just cleaned things up a little around the carb and air filter.
So out of the box this carb has .095 main jets w/ .070 x .052 rods. When the choke opened fully it needed to idle up around 2000 to be steady, so just like last time I felt it was running lean. I had already dialed in the idle mixture screws (both about 1.75 turns out), so I put in metering rods one step richer at low speed (.068 x .052) and it calmed right down. It now idles around 1300 pretty smoothly, but there are a few small stumbles here and there. So much easier to adjust than a Holley though. Never cared for Holleys though. Well, I have about 30 miles on this carb/intake/exhaust and it's running much better than the first 300 I've put on it. Here's to fine tuning it!
So out of the box this carb has .095 main jets w/ .070 x .052 rods. When the choke opened fully it needed to idle up around 2000 to be steady, so just like last time I felt it was running lean. I had already dialed in the idle mixture screws (both about 1.75 turns out), so I put in metering rods one step richer at low speed (.068 x .052) and it calmed right down. It now idles around 1300 pretty smoothly, but there are a few small stumbles here and there. So much easier to adjust than a Holley though. Never cared for Holleys though. Well, I have about 30 miles on this carb/intake/exhaust and it's running much better than the first 300 I've put on it. Here's to fine tuning it!
Nice thread. I think I will go edelbrock aswell! Happy new years
Well I put some miles on the car last night and this morning. The metering rod change was an improvement but power dropped off around 5k as it started to sputter. I installed the next set of rods (Edelbrock #1447 .068 x .047). This is the same low speed / cruise mode, but richer on the transition and power end. Well Brap Brap Brap!! The car went from sorta-driveable to "Come on Max, Faster Faster". It sounds like a street port and from 1500 - 5.5K it's very strong, smooth, and eager. Planted, great throttle response, even seems to shift better. It still has a little bit of stumble/cough, but it's higher and less noticeable. But still, the power drops off there in the secondaries, so I'm going to try the next step up on secondary jets (.098 vs current .095).
Also the idle is not constant, which is why I have it at 1300. It will stay there for 2 miles, or 10, and then start gently hunting up and down (1 - 2k). I can set it to idle around 900 - 1000, but when it decides to randomly start changing it will stall (or climb up to 1500). More adjusting needed. It's only been running for 2 days with this fuel and carb setup.
Okay here's an update and some ranting. The opinions shared in this post are mine and mine alone. If any children or small animals are harmed by them I apologize.
So the Eddy runs okay overall. After warming up it idles pretty steady around 1100, which I'm okay with. Whatever was causing it to "hunt" up and down for a steady idle went away, but it still stumbles above 5000.rpm. I wasn't able to get rid of that by going richer (or leaner) on the secondary jetting. Timing is correct and I have nice blue sparks on all 4 plugs (plugs and wires have less than 500 miles). Original coils, ignitors and cap/rotor have 57k on them and look fine.
So something that bothered me about the Eddy install was the port mis-matching between the carb, spacer and manifold. The RB intake matches very well to the RB 465cm Holley 1848. The following pics are of the Holley's base plate on the manifold. The Holley has 1.5" bores on all 4 corners and the manifold is almost exactly the same. this will naturally make a very smooth transition down the runners.
The 500 Edelbrock is a different story. It has 1.4375" primary and 1.6875 secondary bores (1-7/16" & 1-11/16"). The primaries will be fine but the secondaries would A) possibly hit the manifold and B) have an abrupt "step" in the airflow, where the 1.68 bore suddenly hits the smaller 1.5 bore. This "step" idea is going to get mentioned a lot in the next paragraph.
The Eddy also needs a 1" carb spacer for the electric choke to clear the thermostat and the throttle cable to line up nicely. I couldn't find a spacer with 2 different size holes so I got one with 4) 1.7 or so sized holes to clear the secondary butterflies. And here's where my mental problem starts -- those damned Steps again in the airflow. So the primaries go from a 1.44 bore to a 1.7 and then through a smaller 1.5 opening. Is this bad? How bad? I don't know but every time I look at it I don't like it. The first pic is looking through the spacer up at the bottom if the Eddy. the secondary is fine but the primary has a noticeable step-up.
And here's looking down through the spacer into the manifold, again a sharp step-down with an edge to tumble over.
I know I'm overthinking this but the primaries on a well-sized speadbore carb like the Nikki or the Quardrajet on Pop-Pop's 1980 Chevy are Tiny to give fast airflow and good signal to the carb's circuits. That's why it's bad to oversize a carb - the same amount of air will move at a slower rate over the venturis/boosters/etc and won't have the same "pull" on the fuel circuits, so it will take a lot of adjusting and fiddling and re-jetting to get it to run. That's my basic understanding anyway. A GM 454 with a 500cfm will drive much nicer, and stronger on the bottom end, than a 350 with a 750cfm.
Anyway... So i've spent several weekends rebuilding my Holley, which had major vacuum leaks when I bought it used. It was full of powdery film from repeated drying out, and was just filthy. Oh, and in case I didn't mention it, I don't like Holleys. They come in many more sizes and flavors than Edelbrock, and are infininely more adjustable and aftermarket supported, which is great for racers who travel to different tracks with different temps and altitudes. You can set a holley up for anything running anywhere under any conditions. But it's a messy invasive procedure and I'm not a racer and don't want to deal with it. And they're baboon *** ugly. You can change the metering rods on an Eddy, which essentially rejets the primaries, in 2 minutes without getting gas on your hands, with the carb on the motor in front of the 7eleven, all day till you get it where you want it. If you actually want to change the primary or secondary jets you can do that with the carb on motor too, but it takes 10 minutes. The fuel bowls have anti-slosh baffles in them, the high-idle is easier to adjust, the idle speed is easier to adjust, there's no gaskets to leak, and they;re nice looking carbs. I don't like Holley's by the way.
BUT, the Eddy only comes in 500, 600, 650, 750 and 800 cfm sizes.There are no 1000cfm or double pumpers for the big-time drag racers, and no sub-500's for little engines like ours. I really wish they made something 350 to 400, but my 500 is as small as they go. They're limited, but simple to use and tune for average-joe builders like me. When I had a Ford I was a Ford guy, when I had a Chevy I was a Chevy guy. When I had an Edelbrock (or 7) I was an Edelbrock guy, and now that I have a Holley I'm STILL an Edelbrock guy! LOL
So the Holley ran horribly lean when I first got it (used). that's when I put the Eddy on. But the Holley is better sized and suited for my beehive sized engine, so I decided to give it a full, proper rebuild. In addition to the straight-ahead rebuild I bored out and bronze bushed the throttle shafts and replaced the plastic/teflon bushings as well. Both throttle shafts were loosy-goosey and were found to be vac leaks, and I hoped this would make it run the way it's supposed to.
So the freshly rebuilt carb was put on yesterday after work. swapping a carb seems easy enough, but I had to -
* undo the brake booster vac line from the manifold to take the extra long mounting bolts out (no spacer needed with Holley)
*go buy more fuel line and redo my routing
*buy a different fitting to run my pcv line
*transfer all the throttle linkage bits from one carb to the other
*drink a few beers
*spend about an hour adjusting manual choke cable/linkage (holley has been converted to manual choke, but that's for another post)
*spend another hour starting and restarting car while I adjusted fast and running idle, trimmed idle screws.
And after all that, the Holley still won't run right ! It runs just like the first time, meaning it won't run without the choke. I mean fully warmed up, with thermostat open and rad fan running, it needs the choke mostly closed and idle around 2000 to stay running, just like before. But the header isn't glowing like a neon sign like before (see my avatar), so if it's still a lean/ vac issue it's not as bad. But WTF? It doesn't do this with the Nikki or the $400 Eddy, just the $700 "made for 12A" Holley bird box. I'm gonna call it the birdbox from now on, because every time i see it I want to kill myself. Haha.
So, the Shiny and FUNCTIONAL Eddy is going back on, and I'm going to give the Holley-caust to my worst enemy. But I have plans for the Eddy to fix the "step" issue that bothered me, and maybe help it run a little smoother. I found another 1" pheonolic spacer with bores that match the manifold bores and Eddy primaries. On the secondary, where the spacer matches the manifold but are smaller than the Eddy bores, I will transition from the 1.5 mani to the 1.7, tapering it up. I've ported a few sets of iron heads so this isn't too scary. The primaries should have a straight pretty smooth shot into the engine, and the secondaries should have a much smoother transition. I'll post pics, wish me luck.
Does your Edelbrock have the counterweighted secondary covers? If so then it helps a lot with transition to secondaries to grind the counterweights down.
Edelbrocks are great DD carbs. They drink like a sailor, but they are very trouble free carbs. Never really require tinkering. BUT they are no powerhouse and they do not corner well.
I've never messed with the secondary opening, just the transition springs on the rods. But this is a newer style AVS model with adjustable barn door. There's an adjuster screw/spring in the flapper shaft that adjusts how soon the door opens, similar to adjusting the counterweight like you're talking about.
Ah, this makes me miss playing with my Eddys. Very nice driving carbs. I have a 600 that I'm probably going to list in the FS section soon but it would be fun to try it out again. This time on a streetported 12A maybe.
So a couple weeks ago I did as I said and transitioned the secondaries on a 1" spacer. It did feel a little better, but still bogged down when the secondaries came in. It also smoked now on 0-60 acceleration tests, when I shifted from 3rd to 4th (grey oil/gas smelling smoke). What the.....
Secondaries tapered down from 1-11/16 to 1-7/16".
So, it was too rich and bogging down. I think. My Eddy 500 is a newer style AVS II model, which is pretty slick with annular boosters and barn-door style "vacuum" secondaries. The secondaries are actually 100% mechanically operated, but the flapper (barn door) above opens slower, as needed, to provide a smooth transition. It's supposed to anyway. I've seen people remove the flap (very easy) to make it a totally mechanical secondary, but keeping it can only help (bigger carb on a smaller motor).
But this AVS is jetted much richer than Edelbrock's Performer 500's. I looked up the specs on the traditional Performer 500 and was surprised how much richer this guy is (95 jets instead of 86's). So since my car stinks like gas fumes and bogs on secondary, I'm going to jet down to the Performer 500 specs and see how it goes. I actually rebuilt my Holley again and drove it around all day today. It runs much better than the Eddy did due to the high rpm bogging, but it needs adjusting and I have to completely remove it to change jets. Which REALLY sucks when trying to get a new carb tuned-in. And the secondary bowl got boiling hot and started having hot start issues. Eddy never did that. And the Eddy is just plain beautiful! Eddy, by the way, can be completely re-jetted in about 10 minutes without removal from engine or spilling any gas. Not as tuneable as a Holley, I'll give it to Holley there, but not a MF'in PITA like a Holley either.
I'm torn.
Oh, and I converted both carbs to manual choke. The Eddy was simple, looks clean, and works beautifully. The Holley is complicated, as bulky as the electric choke, and very stiff and difficult to use. The win again goes to Eddy. If I can just get it jetted right I'll be a happy camper. Picture time --
Holley Manual Choke has a lever, a cam, springs, rod, detent ball, is as bulky as the electric choke and doesn't work very nicely. And cost about $30. AND a drop-base filter won't clear it. Boo Holley.
Eddy Manual Choke is just a bracket to mount the cable. Costs about $15. The cable mounts to the lever arm that's already there, after you remove the electric choke canister and linkage-rod. This will allow me to lower the carb without contacting the thermostat housing. Oh, and the choke is very smooth to operate. Win Edelbrock!
Clean and pretty, like a prom date.
So the RB Holley, rebuilt as a 4150 and jetted up, actually ran pretty good and revved up very smoothly through the rpms. The Eddy never did that on the stock jetting, which was too rich and caused bad bogging. BUT, when it got hot it became hard to start, and the fuel pressure (guage) was reading low. The secondary bowl, facing the shock tower, was HOT! Looks cool though. Later this week I'll rejet the Edelbrock and try again. Right now I have two functional carbs, but each has issues.
Have you tried messing with the AVS to allow the Eddy to open up secondaries later? I'm guessing they're being activated too early, causing a bog and rich spot. How I would fix this is 1) More Accelerator Pump to help juice the Primaries. 2) Move AVS a substantial amount so they activate at a higher RPM. 3) This is most important, throw a Wideband o2 on the car and do your testing with it. I have an Innovate unit here for sale if you're in need of one.
Wow thanks RBD. I have an Innovate but haven't used it yet - I pieced it together and need one more cable. I hadn't thought too much about adjusting the AVS flap, maybe because it's new to me. All my other Eddies were regular Performer models. I am going to mess with it later in the week and will definitely try that. It can't hurt, can only help. Thanks for the tip.
Oh yeah, I already have the accel. pump on the biggest shot - I found early on that it liked that best.
12-30-18, 10:56 PM
