can someone please sum up the pros and cons for me ?

i think my carb is going to be manual choke but i want electric!

 

The stock thermostatic "hot air" choke works better than either the fully electric choke or a manual choke.

 

Electric chokes main drawback is due to the fact that they cool down faster than necessary when you shut the engine down. Hot air chokes are the best ,followed by manual, then electric.

 

Hot air, manual, electric oh my!! dang im lost!

 

First, understand that both the thermostatic "hot air" choke and fully electric aftermarket chokes are both AUTOMATIC style chokes. A manual choke is just that - it requires a cable that you must operate yourself. That means it is entirely up to you to open and close the choke, and to know how much choke to give the engine at any particular time. The manual style choke hasn't been used by factory vehicles since the 1960s.

A thermostatic "hot air" choke in conjunction with an electric assist is what Ford used on the stock 1 and 2 barrel carburetors. The way it works is this:

Clean, filtered air from the air cleaner is pulled through the "fresh air" tube (a rubber hose that is connected to the carburetor air horn and attaches to another metal tube) and into the bottom of the choke stove chamber on the exhaust manifold, where the air is heated up when the engine is running. From there, the heated air goes back up through the insulated "hot air" tube (attached on the top of the choke stove chamber on the exhaust manifold) that connects to the choke cap. As the air gets hot, it closes the spring in the choke cap, which allows the choke plate to open up as the engine warms up to run on a leaner mixture.

The "electric assist" portion of the stock choke system does not work on its own like an aftermarket electric choke. In fact, it doesn't have to work at all in order for the hot air choke to be effective. It is only there to "assist" the hot air choke in temperatures above 60 degrees, where it helps the choke come off sooner for cleaner emissions. It doesn't work at all when the weather is colder than 60 degrees. It connects from the choke cap by a wire that connects to the back of the alternator.

The original hot air choke works better because the full opening of the choke plate on the carburetor corresponds with the time it takes for an engine to reach normal operating temperature. The heat from the exhaust manifold opens and closes the choke in direct relation to how hot your motor is.

By contrast, the aftermarket electric chokes go from closed to fully open in less than a minute, which causes hesitations, surging, and stalling unless the weather is warm outside. Another drawback is that an aftermarket electric choke resets every time the engine is cut off, which sometimes will choke your engine when it doesn't need it at all, for example when you stop to get gas and start the engine again. The thermostatic "hot air" chokes do not have this problem. The only advantage to an all-electric choke is that they are easier to hook up because it only involves one wire. <!-- / message --> <!-- sig -->

 

I don't think I've ever had a carbed Ford that wasn't cold-blooded...I consider it normal.

 

I assure you that when these trucks were sold new, they were not cold-blooded. After almost 30 years of service, parts get out of tune, worn out, and vital parts are often thrown away. If your truck is tuned correctly, with the thermostatic choke complete and working correctly, and with the stock thermostatic air cleaner in place and functional, your truck should not be cold-blooded.

The weather got down to almost 10 degrees last winter here in South Carolina, and my own carbureted 5.0 started right up with a single pump of gas and continued running without stalling at all.

 

Lariat,
I had a 67 390 LTD that had the choke stove and a bracket that also held a heater hose up against the spring housing. Apparently belt and suspenders.

 

Thanks guys for all the input, i guess im not gonna take the carb that there selling me.

on what car/truck could i find a good 4bbl i read the autolite 4100 i think it is, is a good carb when you go 4bbl on a 300?

 

Don't get me wrong, I've had every type choke made, and each has it's merits. A manual choke puts things totally in your control and it's pure simplicity is hard to beat.

 

The Autolite 4100 is the best mechanical fuel mixer ever made, and that is what I am running on my 5.0. The Autolite 2100 and the later Motorcraft 2150 carburetors are the 2-barrel versions of the Autolite 4100, and they are just as good. The thermostatic hot air choke and annular boosters make these carburetors run almost as well as modern electronic fuel injection!

I think the Autolite 4100 is going to be too much carburetor for your 300. I would suggest finding an Autolite 2100 or a later Motorcraft 2150 instead. These can be found on Ford trucks with the 302 and 351 engines (and others) from the 1970s and into the early 1980s. These are extremely simple, reliable carburetors that give good performance, driveabilty, AND fuel economy. The Autolite 4100 originally came on sports cars of the 1960s, the most popular being the Mustang. The Autolite 4100 never came on a stock 300 engine or on a truck.

If you really want to go with a 4-barrel carburetor on your 300, another popular option is the Offenhauser intake with a Holley 390cfm carburetor.

 

You'll be hard pressed to find a 4100 just sitting around the yard. Carbs usually get removed and sold in bulk to rebuilders. Core prices for 4100s make them pretty attractive, too.

There are - for all practical purposes - two sizes of 4100. Ones stamped 1.08 are rated at 480 cfm and the ones marked 1.12 are 600cfm. I don't think either one is too much for a 300. They're vacuum secondary, and any vacuum secondary 4-bbl will work fine on a 300. The 1.08 would be preferable, but they tend to sell for more than the 1.12 models.

Your best bet for a 4-bbl is to check your local cl and pick up the cheapest 500-600cfm Edelbrock or Holley electric choke carb you can find. Then put a kit in it, slap it on, and drive it. Maybe you need to tune it, maybe you don't. If you need to tune it, get a tuning manual and only make small changes at a time. Document everything. And make sure the ignition system and timing are dialed in before you assume it's the carb's fault.

 

The 4100 is a great carb, but unless you have an Offy C intake, or a Clifford, with a 300 the 4100 mixing needles are almost on the v.cover, and that makes it a PIA to adjust. The good thing about them is they get great mpg and are easy to rebuild. If you dig around you can find one on epay for about $50.

You want a 4v, imo, for power and mpg. I'd ck CL for a nice vacuum secondary 4v, a holley or an edelbrock. Good luck.

If you do use an Autolite 4100, I had a prob getting it to seal at base due to narrow body. It would be wise to get the 1/8" thick 'gasket-like' spacer from Pony Carbs to avoid v.leaks.

A little aside: When I was 18 I had a jeep with wheel well headers on a V6 buick, and it had manual choke. When I drove by parties I would push in the clutch, pull out the choke and pump the gas, then push the choke back in and dump the clutch. Flames would shoot out the mufflers. I was 18 guys.

 

Hahaha thats badass!!

 

Confession is good for the soul Kevin