4429S carb on my 70 Cuda

[WhiteGP]

I found a Carter 4429S on my new - old Cuda, Should be a 4737S ... The 4429 shows to be for a 68-69 440 so should be OK, as I mentioned earlier the car has a slight low speed surge which the factory manual address's at the start of the 4737 repair section as the low speed idle needles are out of balance. I ordered a set of new needles for a 4737 ( yea, cart before the horse ) and need to lookup if the same needle size, should be but?

My issue is, the factory needles seem to be in a recessed hole in the base, and seem to be STUCK, they wont budge. am I working wit the correct needles ( I'm really not a Carb guy ). The factory repair manual says to pop off the plastic caps to get to the needles, are these the caps above the two "holes" or are the plastic caps just missing.

Someone save me from myself !!!

Thanks

 

[pschlosser]

The (1968) 4429 is an earlier AVS 440 carburetor nearly identical in specifications to the (1970) correct 4737. The 4429 has a single air/fuel mixture screw in the middle. A cleaned and correctly functioning 4429 carburetor should work fine on your 1970 440 engine. But if the carb is dirty, or out of whack in some way, then your faced with two choices:

1. keep the wrong 4429 carburetor and make it work. You would then use 440 maintenance data from the Carter 4429 documentation and 1968 FSM. New carb parts would be for the 4429.
2. find the correct 4737 carburetor and make it work. You would use the 4737 maintenance data matching the model year of your car, such as the 1970 FSM.

The two lower holes, where idle mixture screws are found on later AVS carburetors, like the 4737, were set at the factory and not intended to be set in the field. But that doesn't stop people from buying the 1969 and later AVS Idle Mixture screws and installing them.

The step-up rods between these two models of Carter AVS may not be interchangeable. At least, according to the Carter part lists on these two carbs. They don't seem to share a single step-up metering rod, but this isn't conclusive. And if you lay the new and old metering rods next to each other, and they look identical, then they probably are.

The stuck step-up rod, if that is the rod that is stuck, is a brass rod stuck in a venturi jet, also made of brass. Presuming they are still stuck, I strongly suggest you don't give up on that and soak the areas best you can with penetrating oil and try again. Even soaking the whole carb in diesel fuel for a few days, out in the sun, could be enough to free things up to separate them. Once unstuck, those parts may clean right up.

 

[WhiteGP]

The (1968) 4429 is an earlier AVS 440 carburetor nearly identical in specifications to the (1970) correct 4737. The 4429 has a single air/fuel mixture screw in the middle. A cleaned and correctly functioning 4429 carburetor should work fine on your 1970 440 engine. But if the carb is dirty, or out of whack in some way, then your faced with two choices:

1. keep the wrong 4429 carburetor and make it work. You would then use 440 maintenance data from the Carter 4429 documentation and 1968 FSM. New carb parts would be for the 4429.
2. find the correct 4737 carburetor and make it work. You would use the 4737 maintenance data matching the model year of your car, such as the 1970 FSM.

The two lower holes, where idle mixture screws are found on later AVS carburetors, like the 4737, were set at the factory and not intended to be set in the field. But that doesn't stop people from buying the 1969 and later AVS Idle Mixture screws and installing them.

The step-up rods between these two models of Carter AVS may not be interchangeable. At least, according to the Carter part lists on these two carbs. They don't seem to share a single step-up metering rod, but this isn't conclusive. And if you lay the new and old metering rods next to each other, and they look identical, then they probably are.

The stuck step-up rod, if that is the rod that is stuck, is a brass rod stuck in a venturi jet, also made of brass. Presuming they are still stuck, I strongly suggest you don't give up on that and soak the areas best you can with penetrating oil and try again. Even soaking the whole carb in diesel fuel for a few days, out in the sun, could be enough to free things up to separate them. Once unstuck, those parts may clean right up.

Excellent Information !!!, Thank you so much and you have a good point about a dirty carb, This one as you can see in the pic needs a little TLC, I think I will pull it and give it a good cleaning

 

[Xcudame]

PB Blaster should be on everyone's shelf!

 

[WhiteGP]

PB Blaster should be on everyone's shelf!

Sho is, Amazing stuff

 

[WhiteGP]

Excellent Information !!!, Thank you so much and you have a good point about a dirty carb, This one as you can see in the pic needs a little TLC, I think I will pull it and give it a good cleaning

Excellent Information !!!, Thank you so much and you have a good point about a dirty carb, This one as you can see in the pic needs a little TLC, I think I will pull it and give it a good cleaning

Pulled the carb, much easier to work on and after putting PB Blaster down the low speed ports the needles FINALLY came out, The new needles I bought for the 4737S appear to be the same so waiting on a new carb gasket from Summit, Local stores don't have much of a 1970's parts inventory