Holley VS. Edelbrock debacle

[UC645]

That shouldn't be necessary with an 850 on a 350. I would start with the idle mixture screws almost all the way in (1/2-3/4 out). If the idle mixture is too fat, you're trying to compensate with more air, then it snowballs straight to the hell you're sitting in now.
Read this: https://documents.holley.com/lit705rev.pdf
Power valves are for part throttle, and shouldn't have an effect on idle, unless it has a hole in it....

850cfm? The Holley I’m using is a 600cfm model. I had started with the secondaries closed, but had to open the primaries rather far (never took a measurement) to get the engine to start, let alone idle. Read on Holley’s forums to try cracking the secondaries a bit and that helped tremendously. The shot in the foot is at the time I didn’t know of the .020-.030 rule of the transfer slots.
I think both my idle screws are set at a turn out a piece, I’ve only got two, but shouldn’t I be able to stall the car by bottoming out both screws?

As far as the power valve goes, could it be opening when I put it in gear with the 1000rpm idle?

 

[Neill]

I’ll start by saying this is not a “which one is better?” thread (because it’s the Holley), and more of a “Why does one do things the other doesn’t?” thread.

I recently switched from a 1406 Edelbrock to a 4150 Holley (list # 4776-2) and have had a few issues/quirks with the Holley.
For starters, the Edelbrock would idle down to around 600 rpm and would happily allow the engine to sit in gear without dying, at nearly 500 rpm, the Holley does not come close to these numbers. Even at 1000 rpm idle, with the Holley on the car and it sitting in gear it seems to stall out far easier. When the engine is up to operating temp this gets even worse, with me needing to get on the gas within a second to prevent the car stalling. Does anyone have any ideas on why this is the case? I have rebuilt both carbs, the reason for the switch is I think the Edelbrock is damaged, it leaks fuel out of the bowls when it’s sitting. That carb has already cost me quite a chunk of change in oil from the gas seeping into the pan overnight.

Another quirk with the Holley is that it doesn’t like full choke, but runs quite rough without it when I go to start it. I’m using a manual choke setup, and can not find any tips or tricks to adjusting this so I can use it. Currently I have to hold the choke open about this much in order to get the engine to start or run with it on:
View attachment 157896
Fully closed and the engine dies either due to lack of air or over fueling, I can see fuel pouring out the venturis with the choke on fully. Any tips on fixing this? Or should I stop worrying, leave the choke off, and stick my foot in it a bit while it warms up?

As it stands I know the Holley needs a few things:
A bigger primary squirter
A more aggressive primary accelerator pump cam
A 50cc accelerator pump conversion, or a combination of all 3. I will be taking it back to the bench for by the book adjustments when colder weather hits.
Any advice or suggestions are greatly appreciated, I have been looking for around a week and haven’t turned up any solutions.

The Rochesters, which the Eddy is a copy of, would ,over the years, develop leakage through the lead plugs at the bottom of the bowls. I have sometime lightly peened them over to tighten them up. Others have gone so far as to drill them out, tap threads in the holes, and screw in plugs in the holes. Quick fixes others have tried were to seal over the leaky plugs with, whatever, and I cannot see that working for long.

 

[fleming442]

850cfm? The Holley I’m using is a 600cfm model. I had started with the secondaries closed, but had to open the primaries rather far (never took a measurement) to get the engine to start, let alone idle. Read on Holley’s forums to try cracking the secondaries a bit and that helped tremendously. The shot in the foot is at the time I didn’t know of the .020-.030 rule of the transfer slots.
I think both my idle screws are set at a turn out a piece, I’ve only got two, but shouldn’t I be able to stall the car by bottoming out both screws?

As far as the power valve goes, could it be opening when I put it in gear with the 1000rpm idle?

My bad. I saw that in 500/600 's reply- thought that's what you had. So, just back the idle speed screws all the way off. Like I said, if you (or someone else) never took the blades off the shafts, it should be fine. Yes, you should be able to shut it down with the idle screws. BUT, if you're idling on the part throttle circuit, it's not going to happen. The trick is to only use the idle circuit for idle, then deal with off-idle issues.

Another pertinent question: is the throttle plate single action (all 4 open at the same time) or progressive (primaries then secondaries)?

 

[Neill]

First off, carbs are magic voodoo, especially Edelbrocks. Holleys are ridiculously simple, so it should be an easy fix. The 2 biggest lessons I've learned are float levels and transfer slots. Get them in check, and it's easy street. I still have to revisit the 1406 E-brock I rebuilt for a friend. It had a sunk float; I got it to idle after the rebuild, but the rest of the throttle sweep is trash. Holley Barry on the 67 works pretty damned good for a cobbled together mess. I recently "readjusted" the idle screws, only to put them right back where they were. I don't discount q-jets, but I failed on my attempt and I'm not paying $1000 for a good one. That's EFI territory these days.

And may we now honor the greatest voodoo carb of all time, the immortal Fish !

 

[UC645]

My bad. I saw that in 500/600 's reply- thought that's what you had. So, just back the idle speed screws all the way off. Like I said, if you (or someone else) never took the blades off the shafts, it should be fine. Yes, you should be able to shut it down with the idle screws. BUT, if you're idling on the part throttle circuit, it's not going to happen. The trick is to only use the idle circuit for idle, then deal with off-idle issues.

Another pertinent question: is the throttle plate single action (all 4 open at the same time) or progressive (primaries then secondaries)?

The QuickFuel setup (throttle shafts and linkage only) is a progressive one. Installed per instructions in the box.

 

[UC645]

Alright, did a little testing this afternoon and found a couple of things.
Firstly, I grossly messed up on the squirters, the primary had a .037 in it, factory is .025, secondary had a .028 in it, factory is .032. This change fixed the backfire on sharp throttle input, but it still stumbles if I give it enough throttle to hit the secondaries. I think this won’t be an issue once I get the transfer slots squared away.
gnvair’s trick of removing the choke butterfly worked flawlessly. I just needed to give the carb a couple extra pumps and it fired right up and idled with no issues.
As for the power valve... I had my father watch a vacuum gauge when I put it into gear with the wheels blocked, and vacuum dropped to 8hg. I’ll need a 3.5 power valve according to Holley’s manuals. Although one thing that stumps me is the car will die if I hold the brake on or if it sits in gear with the wheels blocked. Not sure if this is power valve or vacuum leak related, because I ran out of gas, but it’s possible my booster may be on its last legs. Took the booster hose off, kinked it, and engine rpm never dropped. I am using a spacer with a vacuum port since the Holley only has a PCV fitting.
Currently taking the carb off, so I’ll see just how bad these transfer slots are.

 

[melloelky]

Now This is a carb.Got this in the mail @ work today.its a holley tea pot

 

[UC645]

Now This is a carb.Got this in the mail @ work today.its a holley tea pot
View attachment 157966

Now that’s awesome.


My transfer slots on the other hand, sort of aren’t. The primaries are way too open.

And the secondaries aren’t even showing the slot.

Back to the bench it is.

 

[DRIVEN]

Now This is a carb.Got this in the mail @ work today.its a holley tea pot
View attachment 157966

Towering inferno!

 

[olds307 and 403]

Now This is a carb.Got this in the mail @ work today.its a holley tea pot
View attachment 157966

Those came on the old Ford Y block's, correct?