Facebook Click here to find out more!

What Torque Converter do I need?

Mopar Muscle
Item Posts    Sort Order

What Torque Converter do I need?

furiousdriver furiousdriver
New User | Posts: 1 | Joined: 07/13
Posted: 07/07/13
06:35 AM

What Torque Converter do I need?
To start I have had an issue with my engine idling while in gear, every since I replaced the 383 4 bbl with a 440 6 pak.

I'm running #65 metering jets in the center carburetor, the outboard carburetor on the throttle side to #82 and left #80 on the diaphragm side. Currently my power valve is 3.5.

I have good vacuum 16-17 at idle 950 rpms in neutral and a vacuum of 10 in drive idle drops to 650 rpms, but wants to stall.

My cam is the purple cam P4452993 280/280 - 60 duration 474/474 lift centerline 110.

I have spent hours adjusting the center carbs i.e. 63 jets, 64 jets, 5.5 power valve. Tuning all 3 carburetors and I get the same results.

Now I suspect that my torque converter is my problem. Does anyone know what a good match would be for my setup?  

waynep712222 waynep712222
User | Posts: 127 | Joined: 04/13
Posted: 07/07/13
09:18 AM

before i tell you that you might want a torque converter around 1200/1800 stall speed...

i would like to discuss the idle circuit and the idle transition circuit with you...

if you are trying to get it into gear with the idle at about 900.. you are going to find that you have the throttle blades are set exposing too much of the idle transition slot..  this is what causes it to run rich and die when you drop it in drive..

at idle... the fuel is fed out of the round idle feed passages and is controlled by the idle mixture screws...

above idle.. the fuel is fed by the round idle feed passages but also by the idle transition slots ..

the idle transition slots are neat and not well understood..  

waynep712222 waynep712222
User | Posts: 127 | Joined: 04/13
Posted: 07/07/13
09:59 AM

a few things.. if the end carb throttle plates are not sealing as much as possible.  so all the air is coming past the center carb throttle plates..  so it has a chance to pull fuel in..
a warning... improperly sized PCV valves can along with other vacuum leaks can effect the ability to idle in gear..  think power brake booster thats blown out..

PCV flow testing needs to be done at 650 to 700 RPMs...   with a digital tach monitoring RPM.. pinch off the hose or block the end..   the idle should drop between 50 and 70 RPM if the pcv calibration is properly sized.  if it drops less... you need a bigger opening size in the pcv valve.. it it drops more.. you need a smaller opening in the pcv.. manufacturers have started boxing them by shape.. not flow..  since they don't understand.. bigger must be better..  oil consumption and idle speed problems..


lets look at some pictures..
if you look at the right side of this picture.. you will see that the throttle is properly closed and the only fuel coming in is thru the idle discharge hole below the throttle blade.. where its controlled by the idle mixture screw.
C4f4d6c1 1D73 4E65 Be87 F5f83704f02f Zpscca0cc7c


now... lets look at the idle transition circuit... in the right side of the image..  this is with the throttle part way open.. but not far enough open that the air flow is enough to start pulling from the mains...

note that is coming thru the idle transition slot..  the farther open.. the more slot thats exposed below the throttle plate.. so more fuel is fed..   how does that work.. the slot is higher than the thickness of the throttle blade.. so as you open the throttle.. you expose a small amount of slot..  the vacuum pulls a small amount of fuel thru the slot.. because the top of the slot above the throttle blade is not exposed to a lot of vacuum .. it becomes an air bleed.. fine tuning the amount of fuel discharged...  so.. the farther open you have the throttle blade.. the more fuel is pulled from the idle transition slot..

this keeps the air fuel ratio near where it needs to make power.. so you don't have a flat spot off idle..

the idle feed restriction in the metering block and the idle air bleeds control the total amount of fuel pulled thru the idle transition circuit..

3Feefa5f 0903 43C2 A458 64Cc632ced6e Zps4e3280c8


sorry that these are all 4 barrel images..  the holley 2 barrel 2300 models is exactly the front half of a 4 barrel 4150/4160 carb..

perhaps looking at the idle transition slots and how far exposed they should be for a proper idle...


so .. back off the idle speed on the center carb..    you might want to pull the center carb and the base plate off it and verify the throttle plates are properly centered.,. sitting holley and other carbs down on their base opens the throttle and tips the throttle places open exposing them below the base plate face.. and they can get driven out of alignment..  

waynep712222 waynep712222
User | Posts: 127 | Joined: 04/13
Posted: 07/07/13
12:13 PM

FYI... look at this diagram of the main circuit...

this is at wide open throttle... this is where the main jet changes and the main air bleed changes come into effect...

look carefully or print the 4 image i posted..  study them..  changing main jets ... should HAVE NO effect on idle mixture..  or on idle transition on holley style carbs...

Holleymaincircuit Zps726e60b9