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Quadrajet ????

3K views 5 replies 5 participants last post by  fordillac64 
#1 ·
I have a 425 out of a 77 fleetwood in my 64 ford F100. The quadrajet started leaking. I have been told it is very common for these carbs to warp over time and they are pretty much junk at that point. Is this true?

Next, I decided to put a Holley(dont knock me down here) on it as I understand these a bit more. Well obviously the Holley is wider than the Quadrajet. Everyone I have talked to says all I needed was a spread bore to square bore adapter, so I did. Tonight I went to install it and come to findout it will not work. Are the Chevy Quadrajets the same width as a Cadillac's? Just wondering since I have had many Chevy guys tell me all I needed was this adapter to make it work.

Bare with me here. Carbs are my week point on motors but im stubborn so not giving in. Plus I am not real familiar with working on GM material. :/

Any info is very much appreciated!!!!

Thanks!!
 
#2 ·
Quads are very nice carbs in the scheme of carbs. Not sure what people mean by "warp". If you torque down the carb too much, yes the base will warp but that is user error not the carb's issue.

I would have just have bought the intended, stock carb for the 425 and not have worries about adapting this and that. But that's just me and what I did on the 68 Deville I just bought. 250.00 or so for a completely rebuilt, warranteed carb. Put it on, hooked up the linkage, and off it went without issue.

But that is not where you are.

Can you take the holley back? I have heard of Edlebrock's adapting on 425's but not Holleys. Not saying it cannot be done. Anything can be done lol.
 
#4 ·
QuadraJets are good carbs. If it's leaking...fix it.
Only use a Cadillac spec Quad as they are
calibrated for specific applications.
Rebuilding these is not rocket science
and the procedures in rebuilding them are widely available.

I have three Quads on the bench right now that I am about to rebuild.
One Buick 455, a 75 Eldo, & a 78 Eldo.

Go to Quadra-Jet parts.com and get a rebuild kit (about $30) and any other parts
you think need replacing. You will have a correctly calibrated carb that bolts up
without jerry rigging.
 
#5 ·
Get Doug Roe's HP paperback (8 X 11) book on Quadrajets. Everything you ever wanted to know. Google "rochester carburetors doug roe hp book".

I build Olds 455 marine engines, and a well-tuned QJ is the only way to go - bulletproof, accurate, reliable. Install the electric choke upgrade.

Don't try to get an 800 cfm QJ to run on a 425 - use the smaller primary venturi model rated at about 700 cfm or so - and learn how to set the secondary air valve tip-in spring tension.
 
#6 ·
Thanks guys!!! I was MIA for a few days, crazy round here. I was handicapped and a bit inexperienced the night i was installing the adapter. I did go the Holley way. I was already invested into it so kept going this direction I also wanted to get it running so if I decided to sell the drivetrain out of the truck I can allow the potential buyer to here and drive it. The Holley works great so far. It is running a little rich but I have not made any adjustments yet. I bolted it on and it fired and idles real nice. I am going to hang onto the quad for the purpose of selling it with the motor. Or I may just attempt the rebuild for the knowledge and experience. It actually did not take too much modifying to make the Holley work. A couple "T" connectors for vacuum and the adapter plate. Again thanks for all the info.
 
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