Thoughts on Holley carb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jtminton · 07-22-2005, 11:19 AM

Any thoughts on a Holley spread bore carb? My dad has one that needs to be rebuilt, and I was wanting to know if anybody had any experience/advice about it. The number I got off the carb is L6210 3, if that helps. It's at home right now, so I can't post any pics. It would be for my 72 C-20 with a 350. I currently have a Quadrajet on it.

Thanks!

panhandler62 · 07-22-2005, 11:23 AM

The Holley doesn't actually meter quite as well as the quadrajet, but it is dramatticaly easier to tune and maintain. Rebuilding Holley carbs is simplicity itself whereas rebuilding Quadrajets is like putting a puzzle together in the dark while you are drunk.

In practice: the Holley will usualy run better simply because you can keep it properly tuned with almost no effort while the Rochester will often be about half a bubble off plumb.

jtminton · 07-22-2005, 11:27 AM

Quote:

Originally Posted by panhandler62

In practice: the Holley will usualy run better simply because you can keep it properly tuned with almost no effort while the Rochester will often be about half a bubble off plumb.

Yeah, the QJ leaves an ever-present pool of gas on top of the intake, too. It also bogs down when I floor the pedal. I think it's just old.

hgs_notes · 07-22-2005, 02:52 PM

I did a quick check and found an 0-6210-3 which is a model 4165, 650 cfm carb. I'm not positive, but pretty sure its the same as my 4160, just flows a bit more.

I have part numbers for kits and stuff too.

There are some good tuning guides out there, I have an extra book if your interested. They are pretty easy to build and run. Personnaly, I had a spreadbore Rochester with mechanical secondaries before this, and it ran great, but a pain to rebuild. I really like the mechanical secondaries. I might change mine after the next rebuild.

HG

67chevemall · 07-22-2005, 03:01 PM

I really like the mechanical secondaries. I might change mine after the next rebuild.

Never tried mechanical sec. How do they work? Do they open at a set linkage spot?
Vaccum adjusts with springs how do you adjust mechanical ones?

Cheers

hgs_notes · 07-22-2005, 03:12 PM

"I really like the mechanical secondaries. I might change mine after the next rebuild.

Never tried mechanical sec. How do they work? Do they open at a set linkage spot?
Vaccum adjusts with springs how do you adjust mechanical ones?"

Well, I liked them, but didn't have it long enough to mess with. So adjusting is not something I could help with. But yes, the secondaries open by linkage with the throttle. They start opening at part throttle and then fully open with the primaries. I had it when I was about 20, I'm 38 now and the memory is foggy. Anyway, I don't know enough to say one is better than the other for any particular application. I'm sure there is information available now that would have been difficult to come by back then.

HG

*rage'nrat638* · 07-22-2005, 10:07 PM

manual secondarys......
want to lower your gas milage.....just try it......
say your going up a hill and need a bit more pedal.....well ...the rear two are open.....
you get a hell of a lot of power......under your foot.......heck just the sound of the vacuum.......gas sucking is enough to make me sick......
i had mine on for two weeks and removed....
a holley double pumper with manual secondarys has two power valves....

one little back fire.....or run on....there toast....
lighten up the vacuum secondary spring....to get it to open sooner.....

i changed mine to a two barrel....350 3/4 ton.....and am very happy with the power.....the 69 is not a race truck.......i jump in the 85 638 dart engine when gas don't matter......

thats my story and i am sticking to it !!!!!!!!

Nelson · 07-22-2005, 10:16 PM

I have a Holley 4360 Q-Jet (450cfm) with mechanical secondaries, and I like it! It was easy to rebuild too! I suggest to take some pics of it during disassembly, and use genuine Holley rebuild kit. Just my 2 cents!

07-22-2005, 11:19 AM	#1
jtminton II Timothy 4:2 Join Date: Mar 2005 Location: Fort Worth Posts: 361	Thoughts on Holley carb Any thoughts on a Holley spread bore carb? My dad has one that needs to be rebuilt, and I was wanting to know if anybody had any experience/advice about it. The number I got off the carb is L6210 3, if that helps. It's at home right now, so I can't post any pics. It would be for my 72 C-20 with a 350. I currently have a Quadrajet on it. Thanks! __________________ 72 C-20 2WD LWB Custom Camper Deluxe 350 4 Speed "Project Lazarus" MY TRUE PRIDE AND JOY "Dangit, Bobby, people will see that oil stain and think I'm a drunk."

07-22-2005, 11:23 AM	#2
panhandler62 Java Mechanic Join Date: Jun 2005 Location: Martinsburg, WV Posts: 6,763	The Holley doesn't actually meter quite as well as the quadrajet, but it is dramatticaly easier to tune and maintain. Rebuilding Holley carbs is simplicity itself whereas rebuilding Quadrajets is like putting a puzzle together in the dark while you are drunk. In practice: the Holley will usualy run better simply because you can keep it properly tuned with almost no effort while the Rochester will often be about half a bubble off plumb. __________________ Keith 11 Lincoln MKT -- Momma's wagon 13 G37xS -- middle age crazy car 68 C20 Fleetside -- RIP Decorating the whole town up at a cost of $27 ....

07-22-2005, 02:52 PM	#4
hgs_notes GEARHEAD Join Date: Aug 2003 Location: MN Posts: 6,126	I did a quick check and found an 0-6210-3 which is a model 4165, 650 cfm carb. I'm not positive, but pretty sure its the same as my 4160, just flows a bit more. I have part numbers for kits and stuff too. There are some good tuning guides out there, I have an extra book if your interested. They are pretty easy to build and run. Personnaly, I had a spreadbore Rochester with mechanical secondaries before this, and it ran great, but a pain to rebuild. I really like the mechanical secondaries. I might change mine after the next rebuild. HG __________________ If no one knows what you're doing, they can't tell you you're doing it wrong HG's Dream Car Build - Shelby Cobra Kit Build your own adjustable track bar 71 Long Fleet C/10 72 Jimmy 4x4 (Junkyard Jimmy) HG's Plow Truck '78 K35 Dually Bigass Farm Truck HG's thread of miscellaneous stuff

07-22-2005, 03:12 PM	#6
hgs_notes GEARHEAD Join Date: Aug 2003 Location: MN Posts: 6,126	"I really like the mechanical secondaries. I might change mine after the next rebuild. Never tried mechanical sec. How do they work? Do they open at a set linkage spot? Vaccum adjusts with springs how do you adjust mechanical ones?" Well, I liked them, but didn't have it long enough to mess with. So adjusting is not something I could help with. But yes, the secondaries open by linkage with the throttle. They start opening at part throttle and then fully open with the primaries. I had it when I was about 20, I'm 38 now and the memory is foggy. Anyway, I don't know enough to say one is better than the other for any particular application. I'm sure there is information available now that would have been difficult to come by back then. HG __________________ If no one knows what you're doing, they can't tell you you're doing it wrong HG's Dream Car Build - Shelby Cobra Kit Build your own adjustable track bar 71 Long Fleet C/10 72 Jimmy 4x4 (Junkyard Jimmy) HG's Plow Truck '78 K35 Dually Bigass Farm Truck HG's thread of miscellaneous stuff

07-22-2005, 10:07 PM	#7
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	manual secondarys...... want to lower your gas milage.....just try it...... say your going up a hill and need a bit more pedal.....well ...the rear two are open..... you get a hell of a lot of power......under your foot.......heck just the sound of the vacuum.......gas sucking is enough to make me sick...... i had mine on for two weeks and removed.... a holley double pumper with manual secondarys has two power valves.... one little back fire.....or run on....there toast.... lighten up the vacuum secondary spring....to get it to open sooner..... i changed mine to a two barrel....350 3/4 ton.....and am very happy with the power.....the 69 is not a race truck.......i jump in the 85 638 dart engine when gas don't matter...... thats my story and i am sticking to it !!!!!!!! Last edited by rage'nrat638; 07-22-2005 at 10:19 PM.

07-22-2005, 03:01 PM	#5
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	I really like the mechanical secondaries. I might change mine after the next rebuild. Never tried mechanical sec. How do they work? Do they open at a set linkage spot? Vaccum adjusts with springs how do you adjust mechanical ones? Cheers

07-22-2005, 10:16 PM	#8
Nelson Registered User Join Date: Jun 2001 Location: cambridge,ont,canada Posts: 128	I have a Holley 4360 Q-Jet (450cfm) with mechanical secondaries, and I like it! It was easy to rebuild too! I suggest to take some pics of it during disassembly, and use genuine Holley rebuild kit. Just my 2 cents! __________________ Nelson 1970 C10 350 Auto. A/C not Working



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