Autolite 4100 and 289 performer intake

[Cribbs74]

I could use some help. 1972 Coupe 302/T5

I have a rebuilt Autolite 4100 carb that I am trying to mount on an Edelbrock performer 289 intake. The problem I am having is finding the correct spacer that fits the intake and the carb. I bought a generic one off of Ebay, but it overhangs the intake on either side exposing the vacuum channels cut into the spacer. It’s also way too tall at 1”+ thick. Basically I need a spacer that works with the intake and carb is about 1/2” thick and has a PCV port. I can’t find anything like that whatsoever out there.

Ron

 

[Fordboy71]

If you look up a phenolic spacer for 4100 series on a ‘67 - 69 mustang, they came with a pcv port And were 1” thick. I know there are 1/4“ ones out there but they’re too thin for a pcv. Have you considered running off of manifold vacuum? If I remember correctly, there were 2 ports on the back side of a Performer 289. I don’t know if that would increase the chances of fouling a plug though? Maybe someone else here has tried that?

 

[Cribbs74]

I hadn’t considered that. Would the vacuum be the same there? It would certainly alleviate the problem. I can’t see it fouling plugs more at that entry point than the stock location. At least not on a healthy engine.

 

[Fordboy71]

If it is in plumbed into an intake runner Im Thinking it’s the same vacuum?

 

[c9zx]

Spendy but...... Chuck
https://semomustang.com/products/carburetor-spacer-1969-1970-boss-302About .270 thick.

 

[Hemikiller]

PCV should always be plumbed under the carburetor so it is more or less evenly distributed among all cylinders. Since it's a controlled vacuum leak, plumbing it into an individual runner will cause that cylinder to run lean.

I have a Performer 289 on a 302 here and mocked up a couple ideas with a 4100. Nothing I have on hand would seal. I was hopeful the 69-72 429-4V PCV spacer would work, but no dice. IMO, if you have the the ACP part for the 63-67 289, try flipping it hollow side up and see if it seals properly to the carb.

 

[Cribbs74]

Well dang, that really throws a wrench in the works. Thanks for mocking that up HemiKiller I appreciate that.

So now my options are even more limited. I chose the 4100 becaise it’s a simple stock ford carb and the stock air cleaner fits perfectly. $90 for a spacer is pretty expensive Chuck!

I don’t know what to do now... my kid is the one spending his money and it looks like the mistake is mine. I probably should have chose a different intake, but it’s what we had on hand for a 4 barrel. I’ll figure something out. I am down to just a handful of problems to sort through to get this thing on the road.

Do i need PCV? The passenger valve cover vents into the air cleaner. Finding a non vented cap is pretty easy. It’s purely an emissions thing.and where I am that is hardly an issue.

 

[Sheriff41]

Yes, you need a PCV for the health and longevity of your engine. It reduces pressure in the crankcase and prevents blow-by and gasket leaks, among other benefits.

 

[mrgmhale]

I see some nice ponies In Progress with your pony cars. Nice... I look forward to seeing more photos with progress made.

 

[Cribbs74]

PCV wasn’t even in use until 1961 and was put in place for emissions. Before that crank gases were open vented. It certainly won’t prevent blow by as that is a function of piston/ring seal to the cylinder. Having no crankcase vent would certainly cause gasket leaks ,but there are 2 vents. They only benefit I can see with PCV would be less carbon deposit inside the engine. There is absolutely no performance gain, if anything it causes a marginal performance loss having to re-burn already spent gasses. Feel free to correct me if I am wrong. I like to learn.

 

[Cribbs74]

HK, what is the ACP part? Another spacer I presume? Sorry for the dumb question.

 

[Hemikiller]

I'm assuming this is the spacer you bought, it's made by ACP.

https://buyacp.com/parts/carburetor-spacer-289-302-351-4bbl-fm-ec080a/

 

[Cribbs74]

You are correct sir.

 

[351c1971]

Is the problem with the Autolite 4100 or the manifold? I have that PCV spacer on my Edelbrock Performer 351c 2v intake with a Holley 600 CFM carb. with no issues.

 

[Hemikiller]

See if you can install the spacer upside down with the hollow section against the carb base and see how it seals.

Is the problem with the Autolite 4100 or the manifold? I have that PCV spacer on my Edelbrock Performer 351c 2v intake with a Holley 600 CFM carb. with no issues.

The base of the 4100 is hollow, as is the spacer. The Performer 289 has a very narrow carb pad that won't seal the spacer or the carb.

OE intake



Performer 289



4100 underside

 

[351c1971]

Thanks, understood.
Would either of these help?

Holley 4 Barrel 4150 4160 4180 Models Base to Intake Gasket/Insulator .212 Thick
https://www.ebay.com/itm/3824963212...044&customid=db6a6a3eda0a1a7a74b809e398f64fc3
Mr Gasket 3710 Carburetor Heat Shields, Holley/Carter 4 Barrel
ww.speedwaymotors.com/Mr-Gasket-3710-Carburetor-Heat-Shields-Holley-Carter-4-Barrel,288401.html?sku=5503710&utm_matchtype={match_type}&msclkid=2fa84503b54f14f5a51926def7b3b864&utm_source=bing&utm_medium=cpc&utm_campaign=SMI%20-%20Shopping%20(CSE)%20(Bing)&utm_term=4577816663170690&utm_content=Mr%20Gasket%20(Mar4_2020)

 

[Cribbs74]

Ok, just a follow up. I purchased the boss 302 spacer as suggested by Chuck and it seal’s perfectly with the bonus of having a functional PCV. So if anyone is having the same issue you know what to do now.

 

[Spike Morelli]

That Autolite 4100 was an incredibly simple and good running design, Ford should have kept it. By design, having the one-piece body, fuel leaks were kept to a minimum as compared to the Holley design, similar to Carter's AFB series carbs ( which were good also ). When overhauling one of these Autolites, I've always taken the accelerator pump and power valve caps to a flatplate to give them a fresh, flat surface. These two caps are made of soft metal, and can be overtightened, causing them to be warped, but the flatplate sanding tunes 'em right up. Ford manufactured these 4100s in a 600cfm, and a 480cfm, ( I may be off on the smaller version's cfm ) the smaller cfm version has been shown on a chassis dyno to make more horsepower on an automatic equipped car, than the 600. There was a version used on the Hi-Po 289 which had a manual choke. Cooler still, is that if you look topside at one of these, you can see that the venturi boosters are annular, and "downleg" designed. This design was more sensitive to airflow. Ford holds the Patent on that design, and every performance carb made since uses that design,( like Holley )and has to pay Ford Motor Company royalties on using their design. Ford's design staff who came up with that carb were pretty smart.
Speaking of carbs, did you know that the Holley 4160 four barrel, the one that started Holley's reputation for performance aftermarket carburetion, was designed originally for Ford, as original equipment on the 1957 Thunderbird? It gave birth to the 4150 style later on. And if you run a Dominator on your hot rod, you can thank Ford/Holley again, as that carb was designed for Ford's Boss engine program. Interesting.

 

[Spike Morelli]

Just to throw another option onto the pile, Weiand used to offer a manifold for the '65 Mustang called the "Colt 65", and they were one of the few whom made the carb mounting pad square, to work with the 4100 Autolite. They can be found at swap meets, or on Ebay, and they run pretty good, as good as the Edelbrock old F4B and the Cobra. Maybe not what you'd want, but , it works with your carb.

 

[Billw69]

Speaking of carbs, I’m currently in the market. My quandary is: do I strive to find an original style 4150 with 730 to 750 CFM or do I update to a current model carb in the same CFM? It seems the investment dollar wise is pretty close, but is the performance? This is a high quality driver, not a concours restoration. This is a mostly stock engined car (B1), that had a 4160 with 650 cfm on it. It now has a vintage 4150 with 735 CFM. It performs significantly better with the 4150 compared to the 4160.
I’m interested in a double pumper with electric choke if available.
Holley, Dominator, Summit, quick fuel….. what say the brain trust here?