quadrajet rebuild help .

[gwhiz]

I missed the fact that he was working on a non-CCC/strip car. He will also need to replace the HEI and do something about the lockup ckt..

yes ditching the factory 305 for a mild 350 iam building got a hei and replacing the lockup turbo350 for a non lockup,cam and stall speed still up in the air.i got a couple of quadrajets to rebuild trying to figure out if the ones i got are worth rebuilding or is there specific ones that are better to build than others.

 

[jmt455]

Start here:
http://cliffshighperformance.com/buy_book_2.html

Cliff wrote the book on Q-jets (Literally!)
Buy the book and use it; you can do it all yourself.
http://cliffshighperformance.com/buy_book_2.html


There are also a lot of great (free) tech articles on Q-jet selection, re-building and tuning.
Here are a couple of links:

Tips on identifying and selecting Qjets:
http://cliffshighperformance.com/tech_articles.html

GREAT info on selection, tools, rebuilding techniques, tuning:
http://www.crankshaftcoalition.com/...ajet_4MV_carburetor#Planning_and_organization

Good luck and have fun!

 

[bill]

I bought that book....its perfect. It says that 90% of the time, of the 2 size Quads, the 750cfm is fine for most small block applications (towing/marine are the exceptions). Of course, you cant go wrong using an 800cfm carb but you might lose some mpg in the process and it would require diff jets to keep from drowning the carb in fuel. The book also states that the later model (77-80) Quads are best for all around performance and economy, because the evolution of the Quad was at its peak by then. After 1980, the performance priorities dropped off and economy was the goal, and the ccc came into the picture.

 

[techg8]

Use a 76-79 Quadrajet. M4M style
It will be pre computer and will have the adjustable part throttle accessible thru the air horn.
avoid the big block ones because typically they will have more idle air bypass than a 350 (even mildly cammed) will need.
with a mild cammed engine there will be benefits to opening up the idle tubes and idle channel restriction.

All Quadrajets run relatively lean from the factory. Especially the chevy style with the huge air bleeds.

Plan on recalibrating it for your application so it runs right

 

[gwhiz]

Use a 76-79 Quadrajet. M4M style
It will be pre computer and will have the adjustable part throttle accessible thru the air horn.
avoid the big block ones because typically they will have more idle air bypass than a 350 (even mildly cammed) will need.
with a mild cammed engine there will be benefits to opening up the idle tubes and idle channel restriction.

looks like i will be off the junkyard ,hopefully find a good one that hasnt been rigged with all the coat hanger ,bread tie ,and dry wall screws that i have seen in the past.

 

[techg8]

lol yea - and hope no one has been inside it drilling everything out and monkeying up the calibration for you

grab one that looks undisturbed. Sometimes a layer of dirt and oily crud is good - it indicates that there hasnt been much tampering and it can keep the carb core from seizing up the idle screws and baseplate

good luck

 

[bill]

lol yea - and hope no one has been inside it drilling everything out and monkeying up the calibration for you

grab one that looks undisturbed. Sometimes a layer of dirt and oily crud is good - it indicates that there hasnt been much tampering and it can keep the carb core from seizing up the idle screws and baseplate

good luck

Good advice there.....

 

[gwhiz]

lol yea - and hope no one has been inside it drilling everything out and monkeying up the calibration for you

grab one that looks undisturbed. Sometimes a layer of dirt and oily crud is good - it indicates that there hasnt been much tampering and it can keep the carb core from seizing up the idle screws and baseplate

good luck

thanks my first instinct was to look for a "clean looking carb" but like you said who knows what could have been done to it.