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By yknot - 10 Years Ago
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What is the best jet size for a stock 292 with a 600 cfm Holey. Running real rich now with 66.
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By Ted - 10 Years Ago
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Knowing the list number on the carb will help as Holley made no fewer than two dozen different 600 cfm Holleys and they are all for specific applications. As such, there’s a variety of jet and air bleed sizes within that range of carbs. By taking the List number off of the choke housing, specifics on your particular carb can be looked up to determine if the carb is stock or not.
As a general rule, always start with the jet sizes that originally came in the carburetor. If you’ve verified that the 66’s are stock to your carburetor, then you can reduce the jet size by two number increments. If you have to go more than six numbers to make a significant change, then look for other problems within the carburetor or tuneup. Before doing any jet changes, recheck the float levels in both the primary and secondary sides of the carburetor. The secondary side of the carburetor also has a fixed idle circuit and the float level being high in either end of the carb will make the carburetor run on the rich side.
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By Talkwrench - 10 Years Ago
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As above..
I cant seem to find a search function anymore as I was going to put up a link to an old post of mine giving the details you want..
Anyway, from memory I was at either 62 or 64 . 8.5 P/V , brown or black Sec spring, blue pump cam on the second hole, and the squirters where 31 .. NOW just be careful as that is setup for me and Aussie 91 fuel , my 292 likes to be a bit rich I have quite a fast curve in the dissy.
I went to a 450 Holley and it wasn't a revelation.
There is adjustment for the secondary idle, its under the carb tho' , usually not touched but can help you fine tuning idling.
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By Ted - 10 Years Ago
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Talkwrench (12/2/2014)
As above.. I cant seem to find a search function anymore as I was going to put up a link to an old post of mine giving the details you want.. Anyway, from memory I was at either 62 or 64 . 8.5 P/V , brown or black Sec spring, blue pump cam on the second hole, and the squirters where 31 .. NOW just be careful as that is setup for me and Aussie 91 fuel , my 292 likes to be a bit rich I have quite a fast curve in the dissy. I went to a 450 Holley and it wasn't a revelation. There is adjustment for the secondary idle, its under the carb tho' , usually not touched but can help you fine tuning idling.
For the short term, I’ve pinned slick56’s thread regarding the search function to the top of the This-N-That Section. I’ll get with Jim and see what can be done in moving the search query to the top of the list rather than at the bottom where the scroll bar is simply difficult to see and use. Here’s the link to slick56’s thread.
http://forums.y-blocksforever.com/Topic110807.aspx
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By yknot - 10 Years Ago
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Thanks for the help. Going to start with the 64's ans monitor closely.
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By yknot - 10 Years Ago
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I was able to get a new Holley 0-80570 570CFM Street Avenger carb at the Holley Ebay store for $280. The notes indicated that it was setup for low end torque. I am hoping that the secondary spring kit come with it. I would prefer to run in the front 2 most of the time. Anyone have a recommendation pertaining to setup geared towards mileage for a daily driver. 292, Ford-o-matic
Richard
Richardson, TX
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By Ted - 10 Years Ago
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Out of the box jetting and secondary spring is always a good place to start. Most of the 4V Holleys come with a ‘silver’ spring which is middle of the road as far as spring selection goes. Under normal driving, the secondaries will not be opening until the primary throttle blades are maintained at wide open for a short period. Be sure to double check both the primary and secondary float levels as each is a player in fuel mixture control.
Street Avenger carbs are typically metered for engines that have upgraded camshafts which makes them on the rich side if used with very small or stock camshafts. As a general rule, change jet sizes in two number increments but never any more than a total of six numbers. If it takes more than six numbers to correct the fuel mixture, then look for something else to be out of kilter such as the ignition advance curve or cam timing.
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By yknot - 10 Years Ago
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Here are the specs I found on this carb. I do not know about the power valve numbering. Would there be a need to change this if still running rich? Based on the primary jetting I do not think this is going to happen.
CARBURETOR # 0-80570
PRIMARY METERING JET 54
SECONDARY METERING JET 65
PUMP DISCHARGE NOZZLE 0.031
PRIMARY POWER VALVE 85
SECONDARY POWER VALVE N/A
SECONDARY DIAPHRAGM SPRING Silver
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By Talkwrench - 10 Years Ago
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If your motor is in good condition and makes good vacuum I doubt it. SO have looked at the power valve [economy valve] ? 85 / 8.5 should be fine.
It seems like to should be ok out of the box
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By yknot - 10 Years Ago
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The motor has a vacuum of 22 last time I tuned it approx. 2 weeks ago. When I say tune it includes, setting rocker gap at .020, setting the timing, carb idle adjustment on the metering block, carb cleaning, and fuel bowl level set/checked. The vacuum was more, 25, if I set the timing by highest vacuum. However at that timing it pinged a lot under acceleration. I kept backing off the timing until the pinging stopped and the vacuum read nice and steady at 22. The damper does not have timing marks. So I can''t provide and timing numbers. The 292 is a stock rebuild.
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By Ted - 10 Years Ago
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Not using a timing light makes it tough to get an accurate and repeatable tuneup. I’ll suggest re-curving the distributor so that you have more initial advance while the total advance without the vacuum advance hooked up is in the 36-38° neighborhood. For this, you do need to get some timing marks on the damper so you can use a light.
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By charliemccraney - 10 Years Ago
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The damper does have marks. They can be difficult to see. I used some white paint on the tip of a sewing needle to highlight all of the factory marks on mine and add marks up to 40 degrees.
Damper marking is handled in two ways I am aware of. Most have the marks on the damper. Some have the marks on the pointer, multiple points on the pointer, with only one line on the damper. If you have a mismatch of damper and pointer, then you can have difficulty with the timing.
With the vacuum you have, the factory powervalve should not cause a rich condition under normal driving conditions. I have a 570 had had to jet it up quite a lot but my engine is not stock and according to Holley's chart, I was right on the borderline of a 570 or 670, which probably has something to do with it. Run it out of the box and give it what it needs from there. Just tune it correctly don't try any funny stuff like you're hinting at with the secondary spring. I get mid 16 highway mpg which is not bad at all for a truck.
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