Poor running at speed -
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Joined: Mar 2004
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From: manson
Poor running at speed -
1977 F250 / 460 / Carter or Edelbrock carb...
Problems....starts hard...floods easily if you aren't careful. ( not really worried about this )
Once started it idles pretty well when cold and idles perfect when warm.
Accelerates great...although under hard acceleration ( when not fully warm ) it will stumble when the secondaries open. Otherwise, throttle response is pretty crisp for a big old truck.
When the engine is loaded ( acceleration, passing...etc ) it runs perfect. It is when you are just cruising that there are problems. And the problems aren't "big"....there is just a very minor studder or stumble when cruising ( at any speed - any RPM )...you can't really even feel the misfire...only hear it through the exhaust. If you lived on a farm and had old Farmall tractors around you many know what it sounds like...loaded they sounded fine but start rolling down a hill with a load behind you pushing you down a hill and the exhaust would make a dead misfire sound. Am I making a bit of sense?
Problems....starts hard...floods easily if you aren't careful. ( not really worried about this )
Once started it idles pretty well when cold and idles perfect when warm.
Accelerates great...although under hard acceleration ( when not fully warm ) it will stumble when the secondaries open. Otherwise, throttle response is pretty crisp for a big old truck.
When the engine is loaded ( acceleration, passing...etc ) it runs perfect. It is when you are just cruising that there are problems. And the problems aren't "big"....there is just a very minor studder or stumble when cruising ( at any speed - any RPM )...you can't really even feel the misfire...only hear it through the exhaust. If you lived on a farm and had old Farmall tractors around you many know what it sounds like...loaded they sounded fine but start rolling down a hill with a load behind you pushing you down a hill and the exhaust would make a dead misfire sound. Am I making a bit of sense?
Posting Guru
Joined: May 2004
Posts: 2,223
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From: Billings Montana
The first thing I'd do is change the metering rods. What size carb do you have? Without knowing what size rods you have or what size carb you have, try .073 X 047 rods and go from there. You could also play around with different spring combo's as well.
Check to see if your timing is advancing when you rev it up. Your advance might be sticking a little when you lay into it.
Check to see if your timing is advancing when you rev it up. Your advance might be sticking a little when you lay into it.
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From: manson
Hoss....I know nothing about these carbs...let alone what the F a metering rod is. Would a photo of the carb help? Send me a PM with your email and I could email you some photos...or manybe you know of a web site that has some descriptions? Thanks
Mike
Mike
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Joined: May 2004
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From: Billings Montana
Uhhh, sorry guy! If you go to Edelbrock's web site, they should be able to tell you which direction to go to with the tuning. A metering rod is one of the thing that controls the fuel going into the carb. The larger the metering rod, the LESS fuel going through the main jet and visa versa.
Post Fiend
Joined: Mar 2004
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From: Union, Washington
Originally Posted by michaelbrainardatwor
Maybe I will throw my 600 Holley on it instead!
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Joined: Mar 2004
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From: manson
In your opinion...is a 750 Holley too large for the 460 with stock 4bbl intake?
BTW - Figured out why it starts hard..the choke wasn't working properly. Linkage is sticking somewhere. Close the choke and it starts the way it should.
BTW - Figured out why it starts hard..the choke wasn't working properly. Linkage is sticking somewhere. Close the choke and it starts the way it should.
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Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
Yes, a 750 is to large. At 4500 RPMs a 460 only needs about 600 CFM, which by the way is what the factory puts on them. And after 4500 RPMs the stock cam is restricting air flow so bad that you loose, not gain power.
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