383 cui 2bbl replacement
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69_topless
Member
Do you see any improvement in performance going from stock 350cfm 2bbl? I know this is about the only choice from new 2bbl carburetors, but my friend discourage me from this type which tends to starts to be leaking in few years.
I might found somebody who is capable to make a quality job on rebushing the throtthle shaft, so most likely will stay with my original 2bbl. But Holley 4412 is probably my choice if rebuild wont work out.
The Motorcraft 2150 is supposed to be a great carb. I am in contact with this guy Motorcraft 2150 Carburetor Upgrade for Dodge 318 with Carter BBD or Holley 2280 He can set these up for big block cars also. I may do this for the summer, before my magnum/FI swap next winter. I can't get my Carter BBD to work at all.
69_topless
Member
Hi, thanks for the tip. The seller confirmed he can set up the carb for my car. He runs it on his 454cui Chevy, for example.
What are the flaws of this swap, beside using Ford parts on Mopar? Air cleaner fitment?
69_topless
Member
In the end, I'm going to rebuild my original carburetor. I found a local guy who will take care of the throttle shaft play and bought the rebuild kit for the upper part. Will report results once done, thanks to everyone for help so far.
69_topless
Member
Its time to make a update. The axle shaft play ended up sorted very well and upper part was rebuild by a friend. We installed the carb last Sunday and so far everything is perfect.
The car runs great, the shifting become very smooth at light throttle, like never before, probably due elimination of pressure leaks. At medium throttle the shift was always ok, but wow, she is now such a smooth cruiser.
I need to put some miles on her to settle everything down and make final adjustment, but so far so good. I'm glad i have stayed with stock 2 bbl.
There is short walkaround video as a thanks for your help!
The car runs great, the shifting become very smooth at light throttle, like never before, probably due elimination of pressure leaks. At medium throttle the shift was always ok, but wow, she is now such a smooth cruiser.
I need to put some miles on her to settle everything down and make final adjustment, but so far so good. I'm glad i have stayed with stock 2 bbl.
There is short walkaround video as a thanks for your help!
69_topless
Member
I changed the oil recently and hooked up the air pressure gauge to check the carb setting.
What I found on youtube, the shaking needle indicates the wrong idle mixture screw, while values close to 15 are related to late timming setting. I have no RPM meter to check what the idle RMP are right now. Please check this video and give me your advice how to adjust it. Thanks for help.
What I found on youtube, the shaking needle indicates the wrong idle mixture screw, while values close to 15 are related to late timming setting. I have no RPM meter to check what the idle RMP are right now. Please check this video and give me your advice how to adjust it. Thanks for help.
Rough...but running and that is good.
18-20 inches should be your goal with a 2bbl carb.
Put the papers for the stock specs in the bottom of the bird cage.
With today's gas they just don't work anymore.
With that vacuum gauge and a good ear "listen" to what the engine wants.
With engine running,turn in the driver's side idle mixture screw all the way slowly stop right before she stalls.back out by 1 and a half turns.Do the same next side.
Gauge still shaky?? in 1/4 turn increments out,and keep watching the vacuum. If it increases,the engine will smooth out and idle up a little.
It is normal with an engine with some miles on it to have one screw in/pout more than the other--what ever it takes to make it happy.
Goal is have a smooth idle and steady vacuum gauge needle.
If you cannot get any more vacuum by adjusting the screws,bump up the timing,and set the idle.
Remember 18-20 inches makes a 383 happy.
If you have a timing gun with the advance feature,use it.
My last 383 tuning adventure likes 34 degrees all in at 2800 RPM. 10.5-11 degrees all in.
The huge increase in vacuum past 25-30 inches when decelerating tells me engine has some miles on it and possibly minor blowby passing through the rings.
Which notch is your accelrator pump set at?? With duals,you can probably give it an extra shot
Are you running points or electronic ignition??
Hope this helps
18-20 inches should be your goal with a 2bbl carb.
Put the papers for the stock specs in the bottom of the bird cage.
With today's gas they just don't work anymore.
With that vacuum gauge and a good ear "listen" to what the engine wants.
With engine running,turn in the driver's side idle mixture screw all the way slowly stop right before she stalls.back out by 1 and a half turns.Do the same next side.
Gauge still shaky?? in 1/4 turn increments out,and keep watching the vacuum. If it increases,the engine will smooth out and idle up a little.
It is normal with an engine with some miles on it to have one screw in/pout more than the other--what ever it takes to make it happy.
Goal is have a smooth idle and steady vacuum gauge needle.
If you cannot get any more vacuum by adjusting the screws,bump up the timing,and set the idle.
Remember 18-20 inches makes a 383 happy.
If you have a timing gun with the advance feature,use it.
My last 383 tuning adventure likes 34 degrees all in at 2800 RPM. 10.5-11 degrees all in.
The huge increase in vacuum past 25-30 inches when decelerating tells me engine has some miles on it and possibly minor blowby passing through the rings.
Which notch is your accelrator pump set at?? With duals,you can probably give it an extra shot
Are you running points or electronic ignition??
Hope this helps
Last edited:
69_topless
Member
Hi thank you for detailed advice. The car appear to have around 97k miles now and I made complete resto 7? years ago. The engine was checked and found in good condition. Since then, I put around 5k miles on it.
The previous owner switched to electronic ignitions already, so thats sorted out. Notch in accelerator pump needs to check, I have never messed with them. I will try to play with the vacuum gauge following your instruction over the weekend and return with results
thrashingcows
Senior Member
A basic timing light is needed for dialing in your motor and carb....just a simple flashing light so you can see the timing marks. Once you have the base timing set adjust the carb as C-barge mentioned to maximize vacuum. You may need to adjust the rpm up/down a tad as you work with the carb and timing. Make sure to do your carb adjustment when the motor is up to operating temperature as well.
69_topless
Member
Thanks everyone for their inputs. I got the timing gun with RPM indication and possibility of advance setting. So far I was able to make a very quick test after a driving, so the engine was warmed up well. The idle RPM is probably bit too low, it has run at 430RPM and after pushing the pedal once, it stays at 480RPM.
On idle, I set 12 degrees on the gun and I it shows 0 on the marking, it seems no difference with the vacuum advance connected/disconnected and plugged. Then I set 34 degrees on the gun and approximately with 2800RPM, the gun shows 10 degrees BTDC. This mean total timing is 44 degrees, quite too much? With the vacuum advance disconnected, but not sure if well plugged, it shows even 15 degrees BTDC, making it total 49 degrees? This first measurement was very quick, did not had a time to play with it long enough and the reading must be reconfirmed.
But just to make sure, I should plug this hose on the picture. And if necessary, this marked bolt is the right one to loose a bit in order to move with the distributor, right?
On idle, I set 12 degrees on the gun and I it shows 0 on the marking, it seems no difference with the vacuum advance connected/disconnected and plugged. Then I set 34 degrees on the gun and approximately with 2800RPM, the gun shows 10 degrees BTDC. This mean total timing is 44 degrees, quite too much? With the vacuum advance disconnected, but not sure if well plugged, it shows even 15 degrees BTDC, making it total 49 degrees? This first measurement was very quick, did not had a time to play with it long enough and the reading must be reconfirmed.
But just to make sure, I should plug this hose on the picture. And if necessary, this marked bolt is the right one to loose a bit in order to move with the distributor, right?
pomonamissel
Senior Member
go for it afb 4bbl carb on a duel plan intake , duel exhaust will make that a sweet ride . first thing i did to my 65 880 rag with that 383 two bbl . i did intake n carb's (twins and a 6pck) , cam and heads for hard seats , headers . ran just great . opened some eyes when it roll down the road also , lol .
69_topless
Member
Thanks for inputs everyone. Coming back to the topic, I had finally a some time to play with the timming gun and idle adjustment. As a first step, I have increased the idle speed up to 720RPM without gear engaged, it goes down to around 660RPM with the D selected. Numbers are with the air cleaner installed. Shall I reduce a bit the RPM, or its OK?
With the vacuum advance port plugged, I have moved the timming from around 5 BTDC up to 12 degrees. At 2600RPM it shows around 35 degrees before I reinstalled the air cleaner. With the air cleaner in its position, the basic timing went from 12 up to 14 degrees BTC, so I adjusted again 12 degrees with the air cleaner on.
I left a vacuum gauge in the other car, so will play with it later. And I guess, thats where it all starts, adjust the timming in range 10-12? degrees as long as finding biggest vacuum at range 18-20, right? Well, now I´m closer to achieve it.
With the vacuum advance port plugged, I have moved the timming from around 5 BTDC up to 12 degrees. At 2600RPM it shows around 35 degrees before I reinstalled the air cleaner. With the air cleaner in its position, the basic timing went from 12 up to 14 degrees BTC, so I adjusted again 12 degrees with the air cleaner on.
I left a vacuum gauge in the other car, so will play with it later. And I guess, thats where it all starts, adjust the timming in range 10-12? degrees as long as finding biggest vacuum at range 18-20, right? Well, now I´m closer to achieve it.
Your timing light should be much more consistent in its flashing of #1 It is cutting out on you.
Make sure your lead is installed in the correct position and on #1. make sure spark plug is tight and boot is on all the way.
You are on the right path. Test and tune,drive...test and tune,drive. See what the motor likes.
Like a drum kit....Bass,snare,high hats. RPM's,timing,vacuum.
Make sure there is no ping under a load. If there is you can (a) fatten the mixture,or (b) turn the timing down a notch. keep the vacuum at minimum 18 inches,20 max. Keep the idle at 750-800 with today's gas. Anything lower she will load up or stall at the lights.
BTW,Every time you adjust the timing DOUBLE CHECK the timing after you tighten down the distributor to make sure timing did not move. Clamp it down good to avoid any movement when driving.
I had seen too many people complain the timing moved after working on it by leaving it tight enough but loose enough to move by hand..
Make sure your lead is installed in the correct position and on #1. make sure spark plug is tight and boot is on all the way.
You are on the right path. Test and tune,drive...test and tune,drive. See what the motor likes.
Like a drum kit....Bass,snare,high hats. RPM's,timing,vacuum.
Make sure there is no ping under a load. If there is you can (a) fatten the mixture,or (b) turn the timing down a notch. keep the vacuum at minimum 18 inches,20 max. Keep the idle at 750-800 with today's gas. Anything lower she will load up or stall at the lights.
BTW,Every time you adjust the timing DOUBLE CHECK the timing after you tighten down the distributor to make sure timing did not move. Clamp it down good to avoid any movement when driving.
I had seen too many people complain the timing moved after working on it by leaving it tight enough but loose enough to move by hand..
69_topless
Member
Thanks for quick reaction. I put the signal collector probably too far from spark plug 1 as shown on the picture. Should it be as close to the spark plus as possible?
rags
Senior Member
your signal collector is good. spark moves at speed of light. intermittent flash could be from low firing voltage due to bad or fouled plug. points distributor. ever hear of dwell? if timing changes with air cleaner on or off, you have larger problems. nice car. cbarge rules!
Always as close to plug as possible without burning the gun's collector.
69_topless
Member
I will check the spark plugs, their replacement is on my to do list for few years, although I think they works well. Dwell? I have electronic points in distributor installed, so its nothing I should worry about, right?
I will check again the timing with air cleaner on/off, perhaps I did not tight enough the distributor well enough or was misreading the values.
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