sdowney717

I dont know where to get this info.

http://webcache.googleusercontent.co...&ct=clnk&gl=us
found this part reference number
JET and ROD PACKAGE, Metering 4342840 4342847 4342847

I pulled it apart and found the primary rods are 55M and the jets were marked 71, but one of the jets was drilled out to 76.
It would make sense perhaps then the jets might ought to both be 73 since it ran pretty good on the engine.

kd5icr

iTrader: (2)

Dont rely on the fact that the jets were drilled out. Go with the lower of the 2 and stick with 71. and see how it runs for you.Remember Q-Jets only flow what the engine needs. Now there are many guys here that just love Q-Jets and might know what jets go into it, but as far as I can tell that is/was called a thermo quad and was used on dodge cars back in the 70's But what ever you do will have to match the engine setup you are running.

I did find this:
jets are contained in the primaarry and secondary circuits, one
for each barrel. Early CS units had press-in jets retained by o-rings. CS
and 71 TQs have the primary jets in the upper bowl cover. All other
TQs have screw-in primary jets in the main body. All TQs have the
secondary jets mounted in the upper bowl cover. All jets have a part number
prefix of 120-. 72 and later TQs usually have the part suffix stamped
on the jet, primaries: 4XXX, secondaries: 5XXX (or 120-5XXX). The XXX
denotes the size, example: 4098 = 0.098", 5137 = 0.137". CS and 71 TQs
have part number suffixes of 3XX or 3XXX.

I think this might help you find the right jets for it.

sdowney717

it is definitely a quadrajet. It is going on a 392, not a 350 or a Dodge 360. It also has the large main air bleeds in the air horn.
Anyhow, I jetted them both to 73, left the rods at 55M.
idle needles had to be turned out 5 turns.
APT is at 5 turns up from bottom
no nozzle drip
runs alright, maybe a little lean.
I need to run it a while and then look at the plug colors.

What exacly is the affects of the larger main air bleeds versus the smaller main air bleeds on these m4m series carbs? Would there be any advantage to soldering the main air bleeds up and redrilling smaller? I think it might improve the idle circuit. Main air bleeds if smaller means less air mixing with the fuel, therefore a richer mixture, easier to pull fuel vacuum action type of idea, I THINK.

I have a 17080213 which has smaller main air bleeds. I think it idles better.
That one is jetted at 73, has 49M rods, idle screws turned out 1.5 turns and APT is out 1.5 turns, really just barely touching the metering piston pin.