Carburetors - Gary's Musings

[grumpin]

Edward - Is that to me? My 750 CFM Eddy is working great. No problems with it at all.

But that's on a non-stock 460. What engine do you have? (Hint: If you'd put that info in your signature we wouldn't have to ask.) A 600 to 650 CFM carb is a better choice for a 351, if that's what you have.

Now you guys got me thinking new Edelbrock!

Gary, do you know which adapters I need to go from the stock Holley to an Edelbrock on my 460, C6?

I see a 1483 and a 1495 on their website.

Also, does anyone know the fuel pressure on the "hot fuel" setup?

[Edward Michael]

Here are some ideas on the heat shield:

• https://www.amazon.com/Heat-Shielded-Sleeve-Lines-Electrical-Wiring/dp/B015S65VJ0/ref=sr_1_9?s=automotive&ie=UTF8&qid=1486428652&sr=1-9&keywords=fuel+line+insulation

• https://www.amazon.com/Heatshield-Products-204011-Sleeve-Roll/dp/B00FS6CIA6/ref=sr_1_1?s=automotive&ie=UTF8&qid=1486428652&sr=1-1&keywords=fuel+line+insulation

• https://www.amazon.com/010403-0-75-Aluminized-Sleeving-Sheath/dp/B000E267M4/ref=sr_1_2?s=automotive&ie=UTF8&qid=1486428652&sr=1-2&keywords=fuel+line+insulation

And here’s the return-style fuel pressure regulator I’m going to use: https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/regulators/carbureted_regulators/parts/12-803BP. Ford’s hot-fuel handling system is just an orifice that allows any vapor that builds up to escape back to the tank. Or, a very small amount of fuel. But it doesn’t regulate the pressure at all. This one will.

Don’t miss that Jim is selling his Thunder Series carb. He has it on his 460 so it should bolt right on yours.

Thank you Gary.

Any input on ethanol resistant fuel hose for carbureted application?

 

[Edward Michael]

My 650 Thunder will be up for sale soon.

For the Holley you can get the quick change spring kit, so you don't have to take everything apart.

How much for that Thunder 650?

Where's it shipping from?

When is it available?

 

[Rembrant]

I think the Holley's are best for max power, and Carters/Edelbrocks for daily driving - for two reasons. First, in my experience the Edelbrocks come out of the box jetted closer to how I want one. Rusty had a stock Holley 1460 on him when I got him, and the MPG was poor. So I installed an Edelbrock 1406 and not only got better MPG but better part-throttle acceleration. Later I installed an air/fuel ratio meter and found that the Holley was very rich, even though that it had stock jetting. But the Edelbrock's air/fuel ratio was very close to what the engine wanted and provided a much more "crisp" feeling. However, it gave away some power at WOT. Yes, I could probably have tuned the Holley's AFR to get it closer to what the engine needed, especially since Holley's have more things to tune, but why when the Eddy was essentially there out of the box?

The other reason is reliability. In my experience Holleys are prone to problems because they hold gas in with gaskets or fabric. In my youth the bowl gaskets were made of cork, and when the carbs ran dry the cork shrank and you had a leak. Today the better kits have gaskets that don't shrink, but you can still have problems if a ham-handed "mechanic" has over-tightened the bowl screws and warped the bowl or main body. In addition, there's the design flaw of no check valve in the vacuum passage to the power valve. Holley admitted it was a flaw by installing a check valve on newer carbs, and kits are available to fix it on older ones. But forums all over the place have people writing in who have blown power valves due to one backfire because many of the carbs out there have not had the check valve added.

To me the choice is simple - if I'm racing I'll use a Holley, but for my daily driver I'll use an Eddy. Or, the newer Street Demon, which is similar to a Carter or Rochester.

Hey Gary,

Since you guys are discussing carbs here...

I bought some used SBF parts from a local guy, one of which was a 600 CFM Holley 4160 w/electric choke and vac secondaries. The guy told me that the carb was supposed to be only 4-5 years old, but I talked to a guy at Holley and he seemed to think that the carb was the older of two possible years (2001 or 2011).

Anyway, I am pulling my 302 out soon for some refresh work. Not machining...compression and oil pressure are both very good, but the oil pan leaks, both valve covers leak, the intake to block seals are leaking, my factory 2bbl carb leaks, and I need to remove all of the smog equipment and crusty manifolds, cats, etc, etc.

As the truck runs right now, it's actually pretty good on fuel (for an old truck). If I install this Holley 4160, is it going to make this thing a pig on fuel? (My intent was to use an Edelbrock Performer 289 intake manifold). And, part two I guess...if it IS going to make it a pig on fuel, will it be difficult for me to get the thing dialed in and working properly? I was planning to install an A/F gauge, at least temporarily.

I have never worked on or tuned a 4bbl carb before. I've re-jetted lots of motorcycle carbs over the years, and I've tuned EFI engines, but automotive carbs are all new to me. I bought a couple Holley carb books for casual reading to get up to speed on these things, but I'm still green as grass.

I guess option #2 for me is to just buy a reman 2bbl for my truck and button it all back up the way it was (without all the smog equip), and forget about the Holley.

Any thoughts or comments good or bad?

[Gary Lewis]

Hey Gary,

Since you guys are discussing carbs here...

I bought some used SBF parts from a local guy, one of which was a 600 CFM Holley 4160 w/electric choke and vac secondaries. The guy told me that the carb was supposed to be only 4-5 years old, but I talked to a guy at Holley and he seemed to think that the carb was the older of two possible years (2001 or 2011).

Anyway, I am pulling my 302 out soon for some refresh work. Not machining...compression and oil pressure are both very good, but the oil pan leaks, both valve covers leak, the intake to block seals are leaking, my factory 2bbl carb leaks, and I need to remove all of the smog equipment and crusty manifolds, cats, etc, etc.

As the truck runs right now, it's actually pretty good on fuel (for an old truck). If I install this Holley 4160, is it going to make this thing a pig on fuel? (My intent was to use an Edelbrock Performer 289 intake manifold). And, part two I guess...if it IS going to make it a pig on fuel, will it be difficult for me to get the thing dialed in and working properly? I was planning to install an A/F gauge, at least temporarily.

I have never worked on or tuned a 4bbl carb before. I've re-jetted lots of motorcycle carbs over the years, and I've tuned EFI engines, but automotive carbs are all new to me. I bought a couple Holley carb books for casual reading to get up to speed on these things, but I'm still green as grass.

I guess option #2 for me is to just buy a reman 2bbl for my truck and button it all back up the way it was (without all the smog equip), and forget about the Holley.

Any thoughts or comments good or bad?

Grumpin - On the fuel pressure for the hot fuel setup, I don’t know. The problem is that I have the orifice and return ahead of my regulator and gauge, so don’t have a way of measuring since the return bleeds off the excess pressure.

As for those parts, 1483 is for the kickdown linkage to the C6. And 1493 is to relocate the throttle bracket - the one to the rear of the carb that bolts to the manifold. But if you aren’t changing the manifold out you don’t need it. The need arises because some of the manifolds reposition the carb. I know that is the case with most manifolds on Windsors and Clevelands, but it doesn’t seem to be the case on the 460.

Edward - Most new fuel line you can buy today is ethanol resistant. I buy it in bulk at O’Reilly’s and it says that on the side of it.

Rembrant - I’m not a fan of Holley carbs for several reasons, and one is just what you asked about - air/fuel ratio. My experience is that out of the box a Holley is very rich at part-throttle. But, it is possible that the one you have has already been re-jetted to a more reasonable part-throttle AFR. You could figure that out by tearing it down and comparing the jetting to the stock jetting, which would give you a chance to learn how a Holley goes together before installing it. Having said that, several very experienced people on here like Holleys, so don’t take my word for it.

As for tuning, the easiest and most accurate way is with a wide-band meter. I have one that also has a vacuum readout, and that makes dialing in the enrichment circuit much easier since you can see the AFR change and the vacuum where it does by looking at one gauge.

 

[85lebaront2]

Now you guys got me thinking new Edelbrock!

Gary, do you know which adapters I need to go from the stock Holley to an Edelbrock on my 460, C6?

I see a 1483 and a 1495 on their website.

Also, does anyone know the fuel pressure on the "hot fuel" setup?

Fuel pressure on the hot fuel handling package is 5-7 psi according to AllData, I was thinking it was even lower, on the order of 3-6 psi. I know it isn't super high, it depends on the vapor return bleed in the separator to vent bubbles back to the tank.

[Gary Lewis]

Fuel pressure on the hot fuel handling package is 5-7 psi according to AllData, I was thinking it was even lower, on the order of 3-6 psi. I know it isn't super high, it depends on the vapor return bleed in the separator to vent bubbles back to the tank.

More impetus for a page on 460 fuel systems, inc hot-fuel handling. Hmmm, I have a few minutes.....

[grumpin]

More impetus for a page on 460 fuel systems, inc hot-fuel handling. Hmmm, I have a few minutes.....

Thank you Gary and lebaron!

I'll have to decide what to do. Haven't been around carbs much lately, a lot of how it acts is operator induced.

What I've learned lately is don't touch that throttle unless absolutely necessary. And only one pump in the morning!

[85lebaront2]

Thank you Gary and lebaron!

I'll have to decide what to do. Haven't been around carbs much lately, a lot of how it acts is operator induced.

What I've learned lately is don't touch that throttle unless absolutely necessary. And only one pump in the morning!

Ford used to recommend a 600 CFM for the 302s in their muscle parts books back in the late 60s/early 70s, we used to sell a Holley replacement, part number was a 1-191 in I remember correctly. I put one on our 1970 1/2 Falcon with a set of 289 4V heads, 351W exhaust manifolds and used 1969 front pipes, and all the rest of the exhaust was 1970 for a 351C 4V. Intake was a 1965 289 unit like the heads.

[85lebaront2]

I will rise to your bait, and raise you some, Weber is by far the absolute best carburetor, however, a Skinner Union is as simple a piece of machinery as can possibly be, only 2 moving parts, no accelerator pump or choke (strangler as the Brits would say).