Wondering what carbs most are using on stock-ish Cleveland motors..
thanks
John
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Had a Holley 600 vacuum secondary, switched over to a Holley 600 double pumper.
And you like the throttle response of the larger pump shot and mechanical secondaries, right?
Every characteristic changed. Power, response oh mileage went down too!
Day in, day out, the right carb for a standard displacement 351C is a 750 Holley (equivalent to a 650 Demon). Vac secondaries will improve fuel economy, double pumpers will improve throttle response.
In times past, the Holley always required tuning to work properly, they were always too rich out of the box, with insufficient accelerator pump for a Cleveland. I've no experience with the new flavors of carb Holley is selling, if any of them are close out of the box, I doubt it however. The message here is, don't expect to buy it, bolt it on & have the motor pull strong at every rpm without stumbles or bogs.
Running a smaller carb is not a cardinal sin however. It will have stronger signal at low rpm, with the trade off being less torque at higher rpm, and the motor will flatten out sooner. The 750 CAN be tuned to pull just as well at lower rpm as the smaller carb.
The 600 cfm street carb is a Chevy camp thing. That's the carb that is always recommended by the magazines for the sbc operated on the street. The sbc is a high velocity motor that weezes through a set of small intake ports. The Cleveland is a whole different animal, Chevy rules do not apply.
In the '70s & '80s, building motors for clients in California meant having to build a motor that could pass visual inspection & tailpipe emission smog testing. I tuned & built several hydraulic cammed motors with power outputs between 350 to 400 bhp using the spread bore Autolite carb (4300D). That carb was rated by Ford at 750 cfm, I'm sure it flows at least the equivalent of a 700 cfm Holley. I have left the 4300D carb on my motor, I see no reason to change it, there would be nothing gained in doing so. This carb is not as adjustable as a Holley or Demon, and the fuel supply system will run out of steam at some point, but installed on a motor with good vacuum signal at idle & cruise, making 400 bhp or less, this carb works OK.
Your friend on the DTBB, George
In times past, the Holley always required tuning to work properly, they were always too rich out of the box, with insufficient accelerator pump for a Cleveland. I've no experience with the new flavors of carb Holley is selling, if any of them are close out of the box, I doubt it however. The message here is, don't expect to buy it, bolt it on & have the motor pull strong at every rpm without stumbles or bogs.
Running a smaller carb is not a cardinal sin however. It will have stronger signal at low rpm, with the trade off being less torque at higher rpm, and the motor will flatten out sooner. The 750 CAN be tuned to pull just as well at lower rpm as the smaller carb.
The 600 cfm street carb is a Chevy camp thing. That's the carb that is always recommended by the magazines for the sbc operated on the street. The sbc is a high velocity motor that weezes through a set of small intake ports. The Cleveland is a whole different animal, Chevy rules do not apply.
In the '70s & '80s, building motors for clients in California meant having to build a motor that could pass visual inspection & tailpipe emission smog testing. I tuned & built several hydraulic cammed motors with power outputs between 350 to 400 bhp using the spread bore Autolite carb (4300D). That carb was rated by Ford at 750 cfm, I'm sure it flows at least the equivalent of a 700 cfm Holley. I have left the 4300D carb on my motor, I see no reason to change it, there would be nothing gained in doing so. This carb is not as adjustable as a Holley or Demon, and the fuel supply system will run out of steam at some point, but installed on a motor with good vacuum signal at idle & cruise, making 400 bhp or less, this carb works OK.
Your friend on the DTBB, George
Im using a Demon 650, goes great!
Dennis
Dennis
I use Holley 670 Street Avenger. Except for choke and idle speed adjustment it has been great. I'm at 750 feet above sea level and that seems pretty close to the flow setting used at the factory.I replaced a 750DP which was way too rich at idle
Speed Demon 650 replaced a tired original factory carb. Nice idle pulls very strong. Excellent Barry Grant tech support.
sorry, I have SVO windsor. I need to read the questions better.
Thanks Guys,
I have what appears to be a 600CFM 4160 series vac secondary carb currently on the motor. Personally, I've never been a fan of 4160s on a manual trans car. I was actually looking at the 4150 model 80528 Holley Pro series, 750cfm w/ mechanical secondaries. Looks like PI sells it as well, but difficult to tell from their description whether (they) tune/jet it close by application or if it's an out of the box 80528. Hard to tell whether this carb has the large PB vacuum port. I see that the throttle bores are opened up an additional 16th". Anyone run one?
http://www.holley.com/0-80528-1.asp
Perahaps a better starting point for my stock-ish rebuilt motor would be the 82751, also a 750 MS carb, 4-corner idle adjustment, standard 1 and 11/16" throttle bores, looks like it comes with 75/80 jets and 31/28 pump nozzles. The picture of it does reveil the large PB vacuum port. I've got a master jet kit on the shelf somewhere but haven't opened it in a while. Mike Ulrey did a masterful job (as always) on the restoration of the original Holley 780 (and distributor) on my BOSS car that required no further tuning, and Craig Conley did the modified Holley 700 DP on the Paxton/GT350. It too was dead-on.. Thanks all, comments/suggestions much appreciated.
http://www.holley.com/0-82751.asp
I have what appears to be a 600CFM 4160 series vac secondary carb currently on the motor. Personally, I've never been a fan of 4160s on a manual trans car. I was actually looking at the 4150 model 80528 Holley Pro series, 750cfm w/ mechanical secondaries. Looks like PI sells it as well, but difficult to tell from their description whether (they) tune/jet it close by application or if it's an out of the box 80528. Hard to tell whether this carb has the large PB vacuum port. I see that the throttle bores are opened up an additional 16th". Anyone run one?
http://www.holley.com/0-80528-1.asp
Perahaps a better starting point for my stock-ish rebuilt motor would be the 82751, also a 750 MS carb, 4-corner idle adjustment, standard 1 and 11/16" throttle bores, looks like it comes with 75/80 jets and 31/28 pump nozzles. The picture of it does reveil the large PB vacuum port. I've got a master jet kit on the shelf somewhere but haven't opened it in a while. Mike Ulrey did a masterful job (as always) on the restoration of the original Holley 780 (and distributor) on my BOSS car that required no further tuning, and Craig Conley did the modified Holley 700 DP on the Paxton/GT350. It too was dead-on.. Thanks all, comments/suggestions much appreciated.
http://www.holley.com/0-82751.asp
I don't know about all you guys, but I will never buy another holley. I had a 600dp and it worked great if you wanted to keep the mosquitos away. After a few months of driving the engine started to develop a stumble. I,ve owned several holleys over the years and all made my engines stumble after a few months of use. I've started running the Eldebrock750 and have had no troubles for 2 years and it installed with minimul adjustments. also, I had an increase in gas mileage by 2 to 3 MPG. Overall the car performs better and doesn't keep the bugs away.
I would recommend a 4779, Holley 750cfm double-pumper. If you are in a state that is still going to smog test you, then it is probably going to be too dirty at idle for you.
It is intended as a race carb and is already rich at idle to compensate for the leaning out that headers do to the engine.
The idle air bleeds can be leaned out some. Since this requires enlargening them with a pin vise (drilling them larger) you need to know what you are doing with them. Once you go to large, there is no going back.
I ran mine with a "weber plate". This let me change everything with drilling out anything.
It is intended as a race carb and is already rich at idle to compensate for the leaning out that headers do to the engine.
The idle air bleeds can be leaned out some. Since this requires enlargening them with a pin vise (drilling them larger) you need to know what you are doing with them. Once you go to large, there is no going back.
I ran mine with a "weber plate". This let me change everything with drilling out anything.
This is a great acrhive..lotsa gems reguarding tuning.
http://realbig.com/pipermail/detomaso/2003-June/028198.html
http://realbig.com/pipermail/detomaso/2003-June/028198.html
quote:Originally posted by micks74:
...I've started running the Eldebrock750 and have had no troubles for 2 years and it installed with minimul adjustments. also, I had an increase in gas mileage by 2 to 3 MPG. ...
Mick, nice looking car in your avatar, I assume that's your '74 Pantera. The Edelbrock carb was originally known as the Carter AFB, and yes, it is a great carb. Nothing wrong with that choice at all. You are right, the oem carbs like Cater, Autolite, Rochester, etc are less fussy than the Holley. The Holley is very adjustable and lends itself well to modification for motors in a very "non stock" state of tune. The Holley fuel bowls will support tremendous amounts of horsepower. That fuel bowl was designed by Smokey Yunick specifically for racing.
When you get a chance, post some pics of your car in the photo gallery, introduce yourself in the pub. In the meantime, let me welcome you to the deTomaso bulletin board, it's a pleasure having you with us.
your friend on the DTBB
Hello Mick,,, Yes, please post some pic's of your car. It is tuff looking. 
Blue is very nice looking on the Pantera. I would like to get a good look at the rims.
Blue is very nice looking on the Pantera. I would like to get a good look at the rims.
Holly 750 DP. 72 Primary and 80 Secondary.
Holley 650 DP
Holley double pumper of somekind. Not real sure what number it is. Where does it say????
quote:Originally posted by Coz:
Holly 750 DP. 72 Primary and 80 Secondary.
With an 80 secondary jet you gonna have a raw fuel exhaust plume. I hope it doesn't backfire.
quote:Originally posted by DeTom:
Holley double pumper of somekind. Not real sure what number it is. Where does it say????
DeTom, there is a number stamped into the air horn on the primary side. The DP's are 4776(600),
4777(650), 4778(700), 4779(750), 4780(800), 4781 (850).