Hey guys i have a 318 that i just put headers on and i have a holley 600cfm carb. After i installed the headers when i get on it it does bog down it just does go like it should but when the secondaries crack open it just rockets. Should i lean or rich the mixture to make it go better? Also would a 650cfm double pumper work good on it? I can get one from my uncle for free but unsure if it will work better or not. Thanks guys!
Tuning after headers??
- Thread starter bbizelli
- Start date
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daredevil
Well-Known Member
sounds like it could use more pump shot
1wild&crazyguy
Banned
richer.
remember...if it boggs then go's, it's too rich/too much pump shot.
If it cuts out/hesitates then go's, it's too lean/too lil pump shot.
remember...if it boggs then go's, it's too rich/too much pump shot.
If it cuts out/hesitates then go's, it's too lean/too lil pump shot.
Locomotion
Well-Known Member
A double pumper will be too much and harder to tune, especially on a mild 318.
Find out what the carb should have from the factory and what it has now. You can look it up by the carb # on the choke. Then go bigger on the squirters (for "immediate" throttle response) and might have to go bigger on the pump cams if there is a flat spot after roughly the first couple seconds. Gotta check the pump arm adjustments with any pump cam changes. You may have to buy some squirters, pump cams and gasket kits.
Headers may have leaned it out, on the pump circuit as well as the jets.
Hopefully the secondaries aren't opening too quick.
It would help to find a book on Holleys to help you understand and tune them. The books published by HP Books has helped me a lot. They have pump cam charts also, but the carb numbers,carb specs and pump cam specs can be found online.
Gotta go - work starts early.
Find out what the carb should have from the factory and what it has now. You can look it up by the carb # on the choke. Then go bigger on the squirters (for "immediate" throttle response) and might have to go bigger on the pump cams if there is a flat spot after roughly the first couple seconds. Gotta check the pump arm adjustments with any pump cam changes. You may have to buy some squirters, pump cams and gasket kits.
Headers may have leaned it out, on the pump circuit as well as the jets.
Hopefully the secondaries aren't opening too quick.
It would help to find a book on Holleys to help you understand and tune them. The books published by HP Books has helped me a lot. They have pump cam charts also, but the carb numbers,carb specs and pump cam specs can be found online.
Gotta go - work starts early.
I tried a Holley 600 on a 273, then on a 360, could never get that bog above idle out, I had rebuilt the carb, installed a 50cc pump, increased squirter size - nothing worked. Finally just went back to a Edel 600, it works fine
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