What are options to swap the carb on my 1985 F-350 460/auto/4x4?


The factory carb was removed and left out in weather. Another 4b double pumper was put on it before i bought the truck.


I removed that and put a holley 4160 750cfm 4b vacuum secondaries on it.

It just seems to be to much for the motor.


What would be a good replacement? A reman from the parts house is over $500.

 

750 VS should be fine for that truck.
What is it doing (or not doing) that bothers you?
Where did you get your 750?
Was it tuned for a much lighter vehicle?

The stock 4180 is said to be around 625 cfm
I am running a 0-80457 600 cfm Holley and it worked fine out of the box with just an idle mixture tweak.
It's nice not to have run a fuel log for dual inlets.

 

I have a holley 0-80508S on it now.

I pulled it from a 69 f-100 390 running a crane 941 cam.

It just seems to be very rich and surges the motor at idle. when you give it the gas it seems to rev up ok. I was thinking it might be a little to much carb for a stock '85 460.

 

CFM is fine.
You've got 70ci on the 390, if the other truck would idle yours can too.
Where are the mixture screws set?

How is it pulling WFO?

If you want to keep it instead of selling it on, go through it and see how it's jetted.
Set it up at some kind of baseline.

Otherwise slag it on Craigslist and buy something you want.
Maybe an Edelbrock?
They rarely need much of anything out of the box.

 

pulling at wfo is not an option until i get the brakes fixed.

primary jetting is #72

 

Someone on here put the Eddy 1406, which is 600 CFM, on his 460 and it worked well. I wish I could remember who that was. Anyway, that's the carb I'm running on my 351M and I thought it was just right but discovered with a wide-band AFR gauge that it was a bit rich. That might explain why it was just right for the 460.

 

Better rich than too lean.
There's no reason this carb won't work on his 460.
If it won't idle and he can't put it under load there's no way the secondaries are opening.
The mains are not his problem until he can drive the truck.

 

I had a problem with the distributor where it would advance like it should when you got on the gas but it stayed advanced when the motor went back down to idle.

Replaced that, set the timing to 8* for now.

The previous owner changed the distributor to a MSD setup and a double pumper carb. He never got it running right and now I have it. The factory carb and distributor was trash from being out in the weather.

I pulled the carb off my other truck and stuck it on this. Truck fires right up and seems to idle ok. It just seems to me not to be as smooth of an idle as it should be.

Am I missing or over looking something?

 

Do you have an MSD ignition box or the stock DSII?
Have you tried the tuneup basics?
Rotor, cap, wires, plugs, etc...?

 

Reman Stock dizzy, new cap, button, wires, plugs

It will idle and seems to miss every so often

 

I was asking which ignition module you are using?

Is it a regular skip at idle, or does it seem random?

 

its all back stock

its not a constant skip. seems very random

 

Many engines miss at idle. Rusty does. Early on I tried many things to fix it, inc plugs, wires, etc. and I not only adjusted the carb, I swapped it. NADA. So I have gotten used to it.

 

I really think you need to fix the brakes and drive it before you can attempt to tune the carb.
Symptoms went from surging, to not as smooth as it should be, to a random skip at idle.
As Gary said, that's not unusual.

If it's eyewatering rich at idle you should adjust the mixture.
Warm the engine.
Turn the mixture screws in a 1/8 turn at a time and give it a little rev, then let it settle back down.
Do this until you find highest vacuum or highest idle speed.
Reset curb idle to 600 in gear.
Adjust idle mixture again, until highest idle or vacuum is found.
Recheck idle speed and you should be fine.

Gary and I both gave you options for 600cfm carbs if you want to go that way.
Holley shows your carb for a 429 application, it's not too big.

 

Amen! Well said.