1975 460 with 4350 motorcarft carb
 

Run a better carb like a Edelbrock 600 or Holley 600.

that is the spreadbore Motorcraft carb correct?

yeah they sucked when new.
my usual fix is a 1968-71 intake a 4-hole spacer, and a 1411 edelbrock. problem solved.

My '76 460 setup wasn't all that great either. The 4350 had a bad stumble when coming to a stop, sometimes stalling out. I got an adapter plate/spacer to run an Edelbrock 1405 (600 cfm) manual choke on the spreadbore intake.
After some jet and metering rod changes, runs great. I would not go smaller than a 600 cfm though.

That does not bode well at all for me. My 75 F350 (460 powered) appears to have the 4350 right now and studders when it starts or when slowing down, sometimes stalling. Once it's warmed up it's less bad, but is never good.

What's the easiest reasonable solution?

you could get a spreadbore Holley 780. or swap manifolds and go AFB/Edelbrock.

typically if set up correctly, you will even get slightly better mileage

Based on the prices a search just came up with for the 780, I'd say that's an excellent solution. Rebuild kits are cheap as well, so I don't see a problem with it.

Hold on thar...
The Holley spreadbore and the 4350 spreadbore are not compatible. The Holley is based on the Quadrajet design for primary and secondary bore spacing, which is quite different from the 4350. The 4350 does not share primary/secondary centerlines like the Holley or Quadrajet does, but rather has the primaries bored closer together in the carb base.

There is an adapter available, but sometimes hard to get, which would be one of the cheapest solutions but you are still gonna need another carb. If you can find a used 429 or 460 intake somewhere for sale that uses a square bore design, grab it, or get yourself an Edelbrock Performer intake and enjoy years of performance technology that is programmed into this nice intake manifold.

Here is the adapter from Summit: Part number TRD-2199
http://store.summitracing.com/partde...0&autoview=sku

Kinda pricey at $57.00, but will do the trick. Also works like a regular 1 inch carb spacer to improve low end torque. What I did was scrounge the junkyard until I found an OEM aluminum carb spacer that was made for a square bore. I then hand-machined the bottom of the bores to match my intake manifold, using an old gasket as a pattern. I just blended the ports smoothly and I got a great working setup that cost me all of $2 for the spacer and a little more money for a good used Edelbrock carb off ebay.

Shoot, had I known this adapter was available 10 years ago, I might have bought it instead of finding a different cast iron manifold to replace that turd with. Had I know the earlier 460s had quadrajets on them, I woulda found one of them manifolds instead, and tapped my buddies tuned and tweaked jobs he had for his chebbies.

I would only go with the Edelbrock Performer if I needed EGR provisions, (essentially its a stock manifold, only aluminum) otherwise I would use a better manifold like the RPM, or the Weiand Stealth.


https://static.summitracing.com/glob...trd-2199_w.jpg

Now i got something of a dumb question. Did ford put a squarebore carb on 460's with the same EGR setup that the 4350 has under the spacer?

I took an air grinder and opened up my stock EGR plate so that the secondaries on the 750 Edelbrock carb would open and bolted it up. That way the carb is sitting at stock height. It has a lot of bottom end snap and no flat spots. I did try several times to rebuild the 4350 but that thing is a piece of crap. I tried to run it through Calif smog. The thing passed emmissions great but they wouldn't pass it because of the Edelbrock. I put the 4350 back on and limped back to the smog station. The emissions were right at the top of allowable range and barely passed but they gave me the smog cert. I limped back home and put the Edelbrock back on. I have since registered the truck at my home in Arizona and no longer have to worry about it.

Gary, make sure your truck registration, and license match states. Big money fines if you don't. There is more mumbo jumbo about requirements for changing to a CA license, taking a job here, kids enrolled in school yada yada yada, AND there is a hotline for snitches to tell on folks who run out of state registration.

as far as I know the only 385S to run a Q jet were early 69 429CJs.

I like to run the stock 68-69 Lincoln intake with a 1" 4-hole spacer and a 1411 edelbrock carb. the performers (non EGR and the RPM version) are also great. I have never had much luck with any single port intake on a 385 series.

You ever try a Weiand Stealth?? I had one on my 460, that thing ran very well. The only beef I had with that setup, and the carb (Demon 650, which flows more like a Holley 750) was that I would get surging at idle, in granny low (with the clutch out.)

Speaking from experience, you have to be careful when trying to play god with carbs. The holley 780 is a better carb, but may have too much CFM if your engine is stock. Here is a post that may be of some use.

https://www.ford-trucks.com/forums/4...ft-4350-a.html