Help tunning Holley 600

66 Racer · 08-07-2001, 10:36 PM

Hey,

I have a 289 V8 with a holley 600 cfm 4 bbl carb. Im no expert to tunning carbs, well no experience, but i want to learn. My carb needs tunning so I wanted to mess with it, any tips?

I used to tune little .12-.15 2 stroke engines with 3 needle carbs so i have some basic knowledge about carbs, i was good with those so im hoping i can transfer some of that knowledge and the "ear" for finding the optimum performance setting.

I have only been able to find 3 needles on my carb, im sure there are more on my carb, i found the idle needle which needed to be opened a bit, and then I also found two little screws/needles torwards the front of the carb on each end.

Any tips will be greatly appriciated. A general explanation on the effect of rich and lean on these engines would be good too. I worked with .12 engines off radio controlled cars which I believe are the opposite that 4 stroke V8 blocks, since leaner meant more power on them. They also ran about 20% nitro mixtures.

Thanks a lot, i enjoyed messing with carbs on those little 2 strokes and want to do the same on my stang!

---Anthony

------------------
Under Construction 66 Coupe
-289 V8 - 600cfm Holley -Tri-Y Headers - Flowmaster 2.5 dual exaust, Centerforce Clutch

David Fulford · 08-08-2001, 07:59 AM

Well the 2 screws on the front of the carb are the mixture screws. I think they are also refered to as the fast idle screws.(may be wrong on that one) As far as running lean, this can cause your engine to be hot and of course running rich can cause plugs to foul etc. How to find the optimum mixture I still don't know without some sort of oxygen sniffer in the exhaust. A basic rule of thumb is to get the car running, turn the screws clockwise, until the engine runs rough and then back the screw out about 1/2 to a full turn. Do the same on the other side. Turning the screws clockwise makes it a more lean mixture and turning them counter clockwise makes a more rich mixture. Someone else on here probably has way more knowledge than me but this is my $.02. Good luck with it.

------------------
1969 fast back; yellow; weld wheels; 302 roller with GT-40 heads; 3:55 gears; 5spd T-5; MSD 6AL; E-303; flows; Hedman headers;

David Fulford · 08-08-2001, 08:02 AM

Well the 2 screws on the front of the carb are the mixture screws. I think they are also refered to as the fast idle screws.(may be wrong on that one) As far as running lean, this can cause your engine to be hot and of course running rich can cause plugs to foul etc. How to find the optimum mixture I still don't know without some sort of oxygen sniffer in the exhaust. A basic rule of thumb is to get the car running, turn the screws clockwise, until the engine runs rough and then back the screw out about 1/2 to a full turn. Do the same on the other side. Turning the screws clockwise makes it a more lean mixture and turning them counter clockwise makes a more rich mixture. Someone else on here probably has way more knowledge than me but this is my $.02. Good luck with it.

------------------
1969 fast back; yellow; weld wheels; 302 roller with GT-40 heads; 3:55 gears; 5spd T-5; MSD 6AL; E-303; flows; Hedman headers; Holley 600;

Brian Browning · 08-08-2001, 11:37 AM

There's a book, I think its called "Rebuiling Holley Carbs" or "everything you always wanted to know about holley carbs" or something like that. I bought a copy at Books-a-Million for about 15 bucks. Its good reading. I'll try and remember to get the exact title when I get home tonight.

Also, you can hook a vacuum gauge to your manifold vacuum. Adjust one side idle screw for the max vacuum, then do the other side. After you get this right, you'll need to adjust your idle set screw.

Hope this helps.

------------------
65 convertible
'66 289 Hi Po motor, 351 heads, headers, duals, shelby intake, petronix,
4 speed top loader, 389 rear, road demon

08-07-2001, 10:36 PM	#1
66 Racer Registered Member Join Date: Jul 2001 Location: West Covina, CA Posts: 77	Help tunning Holley 600 Hey, I have a 289 V8 with a holley 600 cfm 4 bbl carb. Im no expert to tunning carbs, well no experience, but i want to learn. My carb needs tunning so I wanted to mess with it, any tips? I used to tune little .12-.15 2 stroke engines with 3 needle carbs so i have some basic knowledge about carbs, i was good with those so im hoping i can transfer some of that knowledge and the "ear" for finding the optimum performance setting. I have only been able to find 3 needles on my carb, im sure there are more on my carb, i found the idle needle which needed to be opened a bit, and then I also found two little screws/needles torwards the front of the carb on each end. Any tips will be greatly appriciated. A general explanation on the effect of rich and lean on these engines would be good too. I worked with .12 engines off radio controlled cars which I believe are the opposite that 4 stroke V8 blocks, since leaner meant more power on them. They also ran about 20% nitro mixtures. Thanks a lot, i enjoyed messing with carbs on those little 2 strokes and want to do the same on my stang! ---Anthony ------------------ Under Construction 66 Coupe -289 V8 - 600cfm Holley -Tri-Y Headers - Flowmaster 2.5 dual exaust, Centerforce Clutch

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08-08-2001, 07:59 AM	#2
David Fulford Registered Member Join Date: Oct 2000 Location: Charlotte NC Posts: 193	Well the 2 screws on the front of the carb are the mixture screws. I think they are also refered to as the fast idle screws.(may be wrong on that one) As far as running lean, this can cause your engine to be hot and of course running rich can cause plugs to foul etc. How to find the optimum mixture I still don't know without some sort of oxygen sniffer in the exhaust. A basic rule of thumb is to get the car running, turn the screws clockwise, until the engine runs rough and then back the screw out about 1/2 to a full turn. Do the same on the other side. Turning the screws clockwise makes it a more lean mixture and turning them counter clockwise makes a more rich mixture. Someone else on here probably has way more knowledge than me but this is my $.02. Good luck with it. ------------------ 1969 fast back; yellow; weld wheels; 302 roller with GT-40 heads; 3:55 gears; 5spd T-5; MSD 6AL; E-303; flows; Hedman headers;

08-08-2001, 08:02 AM	#3
David Fulford Registered Member Join Date: Oct 2000 Location: Charlotte NC Posts: 193	Well the 2 screws on the front of the carb are the mixture screws. I think they are also refered to as the fast idle screws.(may be wrong on that one) As far as running lean, this can cause your engine to be hot and of course running rich can cause plugs to foul etc. How to find the optimum mixture I still don't know without some sort of oxygen sniffer in the exhaust. A basic rule of thumb is to get the car running, turn the screws clockwise, until the engine runs rough and then back the screw out about 1/2 to a full turn. Do the same on the other side. Turning the screws clockwise makes it a more lean mixture and turning them counter clockwise makes a more rich mixture. Someone else on here probably has way more knowledge than me but this is my $.02. Good luck with it. ------------------ 1969 fast back; yellow; weld wheels; 302 roller with GT-40 heads; 3:55 gears; 5spd T-5; MSD 6AL; E-303; flows; Hedman headers; Holley 600;

08-08-2001, 11:37 AM	#4
Brian Browning Registered Member Join Date: Sep 2000 Location: Hattiesburg, MS, USA Posts: 86	There's a book, I think its called "Rebuiling Holley Carbs" or "everything you always wanted to know about holley carbs" or something like that. I bought a copy at Books-a-Million for about 15 bucks. Its good reading. I'll try and remember to get the exact title when I get home tonight. Also, you can hook a vacuum gauge to your manifold vacuum. Adjust one side idle screw for the max vacuum, then do the other side. After you get this right, you'll need to adjust your idle set screw. Hope this helps. ------------------ 65 convertible '66 289 Hi Po motor, 351 heads, headers, duals, shelby intake, petronix, 4 speed top loader, 389 rear, road demon