QuadraJet Info needed - Please
#1
QuadraJet Info needed - Please
Is this a good board to post a new thread requesting some advise on Q-Jet tech info?
I did a search and it seemed like there's a few guys here who have more knowledge than I do.
Basically it's a '70 4WD that's been Frankensteined.
I have a 700R-4 behind a 327
It's not very built up;
8.5:1 CR, small cam, shorty headers, performer intake...
I have some old Q-Jets and I picked one that looks like it ought to work out. It isn't too damaged and the linkage will fit with no mods.
So that's a starting point
There was someone here in the past who has some reference info on matching model #s to jetting.
That's the sort of info I'm looking for
My carb # 7044502BM (278)
It has 69 pri jets and 39B needles, CK sec needles and a U hanger
The Power Piston spring is sort of medium, compared to some others that I have around
These are not the jets/needles that came originally with the carb
I have had success in the past, jetting Q-Jets, but it was always using a carb that was original equipment on the engine, so that made things simpler.
On the one I have, it's just something that I picked up somewhere, and it had the jets and needles removed.
I chose to use this one out of a collection that I have because it matches the linkage for my trans and it's originally a Chevy carb.
I bushed the primary shafts already and I'm rebuilding it.
I'll be trying it out today. I just wanted to post something because I'm anticipating needing to make some changes.
Thanks in advance
I did a search and it seemed like there's a few guys here who have more knowledge than I do.
Basically it's a '70 4WD that's been Frankensteined.
I have a 700R-4 behind a 327
It's not very built up;
8.5:1 CR, small cam, shorty headers, performer intake...
I have some old Q-Jets and I picked one that looks like it ought to work out. It isn't too damaged and the linkage will fit with no mods.
So that's a starting point
There was someone here in the past who has some reference info on matching model #s to jetting.
That's the sort of info I'm looking for
My carb # 7044502BM (278)
It has 69 pri jets and 39B needles, CK sec needles and a U hanger
The Power Piston spring is sort of medium, compared to some others that I have around
These are not the jets/needles that came originally with the carb
I have had success in the past, jetting Q-Jets, but it was always using a carb that was original equipment on the engine, so that made things simpler.
On the one I have, it's just something that I picked up somewhere, and it had the jets and needles removed.
I chose to use this one out of a collection that I have because it matches the linkage for my trans and it's originally a Chevy carb.
I bushed the primary shafts already and I'm rebuilding it.
I'll be trying it out today. I just wanted to post something because I'm anticipating needing to make some changes.
Thanks in advance
Last edited by BK87S10; 02-11-2019 at 12:44 PM.
#3
I think the Engine & Transmission section works. Fullsize tech could work as well.
I have a few different books on Q-Jets that I have collected over the years. One of the best is , but I haven't looked at it in probably almost 10 years since I rebuilt the carb on my '74. I seem to remember another book that I referenced at the time as well, but do not recall it off the top of my head and will have to look for it when I get home later. It might have been though. Let me see what I can dig up when I get home.
As far as model numbers to metering rods, etc...THIS SITE has one of the most comprehensive lists for secondary metering rods, but that is just the rod specs based off of the id code that I think is on the rod itself.
Here is an article I just found that give you some details straight away -- Q-Jet Carburetor Basic Tuning Techniques.
One thing that is a reoccurring theme when people start modifying q-jets is the tendency to over fuel on the secondary side which is where the quadra-bog nickname came from.
I have a few different books on Q-Jets that I have collected over the years. One of the best is , but I haven't looked at it in probably almost 10 years since I rebuilt the carb on my '74. I seem to remember another book that I referenced at the time as well, but do not recall it off the top of my head and will have to look for it when I get home later. It might have been though. Let me see what I can dig up when I get home.
As far as model numbers to metering rods, etc...THIS SITE has one of the most comprehensive lists for secondary metering rods, but that is just the rod specs based off of the id code that I think is on the rod itself.
Here is an article I just found that give you some details straight away -- Q-Jet Carburetor Basic Tuning Techniques.
One thing that is a reoccurring theme when people start modifying q-jets is the tendency to over fuel on the secondary side which is where the quadra-bog nickname came from.
#4
Thanks for the replies
I have edited the original post with some of the info requested.
I have the Doug Roe book already, and it has got me through a few other modded Q-Jets fairly successfully.
This particular build is unique though, because I picked the carb up at a scrapyard... Or is it the one I got when I helped my neighbor with his spring cleaning?
Anyhow, it had no jets or needles and I'm not sure what vehicle it came from.
Ill have a look at the links provided
Thank You - swartlkk
I just downloaded that tech article
Good Stuff
I have the Doug Roe book already, and it has got me through a few other modded Q-Jets fairly successfully.
This particular build is unique though, because I picked the carb up at a scrapyard... Or is it the one I got when I helped my neighbor with his spring cleaning?
Anyhow, it had no jets or needles and I'm not sure what vehicle it came from.
Ill have a look at the links provided
Thank You - swartlkk
I just downloaded that tech article
Good Stuff
Last edited by BK87S10; 02-11-2019 at 01:00 PM.
#6
Thanks
The article in the link has exactly the info I needed.
I have numerous Quadrajets that I have scrounged over the years, an I just happened to luck out and I picked one that the article lists as a '74 truck carb.
I put some jets and needles in there that match fairly closely and it works wonderfully! ...At least well enough that I'm at a sensible starting point for fine tuning.
I have numerous Quadrajets that I have scrounged over the years, an I just happened to luck out and I picked one that the article lists as a '74 truck carb.
I put some jets and needles in there that match fairly closely and it works wonderfully! ...At least well enough that I'm at a sensible starting point for fine tuning.
Thread
Thread Starter
Forum
Replies
Last Post
WolfsK5
Full Size K5 (1969-1991) GMT415 (1992-1994) Tech
0
11-19-2018 07:02 PM
Terryst48
Full Size K5 (1969-1991) GMT415 (1992-1994) Tech
2
07-09-2018 05:40 PM
1982blazed
Full Size K5 (1969-1991) GMT415 (1992-1994) Tech
7
07-14-2010 09:32 PM