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Hi I have a carburetor question. I have a 67 Mustang Coupe with the numbers matching 289. I number of years ago I paid a lot of money for an Autolite 4300 carb. I didn't find out until I was having problems that it did not have a very good reputation with Pony Carburetor's web site. Anyway, I want to get it off the car because it leaks!

I am looking at jegs right now and they have Demon 525cfm carbs on sale. Apparently they are good street carbs. I am wondering if they have a good reputation?

Thanks!
 

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they are excellent carbs for the money, I would pay a little extra and get a road demon vs a "jr" as they are more tunable. I have run lots of demons and they run great, theres a guy on ebay who sells new and remanufactured demons, I've ran 3 remans so far from him and they are perfect. Up to a 625 road demon will work great.

http://stores.shop.ebay.com/BARRY-GRANT-DEMON-CARBS-AND-MORE__W0QQ_armrsZ1
 

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For a dead stock 289 the Edelbrock 500 cfm is a great carb. Odds are that you will bolt it on and not have to mess with it. And it will NOT leak unless the floats are set wrong.
 

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Carbs are always a preference question, everyone has a favorite and had trouble with others. I used 2 different holley 600cfm and couldn't get them set right and came across a slightly used Demon Jr. 625 electric choke and installed it on a Weiand Stealth on a stock 289. Runs like a champ, 4 corner adjusting screws and glass sights for float level really help when adjusting. Also seems very compact compared to the Holleys, I think if I ever upgrade to a dual carb I could go with 525's with no space issue between carbs or the distributor.

Being a single feed vs. dual feed Demon my mpg should be better. I'm installing my 289 stroked to 333 and hope the Demon Jr. will still be sufficient (think it will) with a little adjustment.

I had to put a couple of dimples in my drop base to clear the levers for the choke, don't know why they don't inset those? I made a mark to line up the lower pan when I reinstall. I also had to fab up a throttle rod as the stock one wouldn't line up correctly, a piece of 1/4" alum rod used a die to cut threads and a couple of ball/sockets from Summit added to each end ~$12 total. It certainly is the best looking carb I've owned! A little bit of aluminum polish really makes it shine.
Jon
http://i194.photobucket.com/albums/z192/jkoed/1967%20Mustang%20Coupe/Engine/Demon2.jpg http://i194.photobucket.com/albums/z192/jkoed/1967%20Mustang%20Coupe/Engine/Demon3-1.jpg
 

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As long as the cam hasn't been changed the 525 would be the size we prefer on the 289. As mentioned the Road Demon vs the Road Demon Jr does have a little advantage as it used a rear metering block so it can be rejetted front and rear. It is also a dual line carburetor vs. the single inlet found on the JR.
 

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JonK said:
Carbs are always a preference question, everyone has a favorite and had trouble with others. I used 2 different holley 600cfm and couldn't get them set right and came across a slightly used Demon Jr. 625 electric choke and installed it on a Weiand Stealth on a stock 289. Runs like a champ, 4 corner adjusting screws and glass sights for float level really help when adjusting. Also seems very compact compared to the Holleys, I think if I ever upgrade to a dual carb I could go with 525's with no space issue between carbs or the distributor.

Being a single feed vs. dual feed Demon my mpg should be better. I'm installing my 289 stroked to 333 and hope the Demon Jr. will still be sufficient (think it will) with a little adjustment.

I had to put a couple of dimples in my drop base to clear the levers for the choke, don't know why they don't inset those? I made a mark to line up the lower pan when I reinstall. I also had to fab up a throttle rod as the stock one wouldn't line up correctly, a piece of 1/4" alum rod used a die to cut threads and a couple of ball/sockets from Summit added to each end ~$12 total. It certainly is the best looking carb I've owned! A little bit of aluminum polish really makes it shine.
Jon
http://i194.photobucket.com/albums/z192/jkoed/1967%20Mustang%20Coupe/Engine/Demon2.jpg http://i194.photobucket.com/albums/z192/jkoed/1967%20Mustang%20Coupe/Engine/Demon3-1.jpg
The choke rod and levers were put outside of the airhorn area to help in the flow of the carburetor and not disturb the air. Sometimes you have to dimple the air cleaner as mentioned while others you dont. I have one on a 69 Cyclone and am using the original air cleaner un-modified.
 

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Tech @ BG [/quote said:
The choke rod and levers were put outside of the airhorn area to help in the flow of the carburetor and not disturb the air.
Thanks for the reply BG, I understand it's on the outside for better flow, it just seems it could have been flush set with the outside and use a curved lever to sit more flush with the shape of the outside horn. I only needed a little bit to clear my base w/o modifying, it just worried me if it ever hung up and kept my choke closed.
Otherwise really impressed with the carb.
Jon
 

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Discussion Starter #8
Thank you for all the replies! I have some more questions. I agree the Road Demon would be better than the Jr. The only thing I noticed in the descriptions is the Jr. says it is calibrated for fuel economy and the Road Demon is calibrated for performance. Does that make a difference? I am looking for fuel economy. But the price difference isn't much so I will probably go with the 525cfm Road Demon. Also, do I need the option with the Ford kick down? I think my original linkage has its own kick down set up. Glad to hear Demon carbs work well, and they are a sharp looking carb.

Thanks!
 

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The Jr. has a single inlet vs the Demon double inlet/dbl. pumper I assume which lowers your economy. I used my Jr. to run the 1/8mi. in stock trim and it sure didn't stumble or limit my speed.

As stated by the BG rep I think the double is overkill for the 289ci. but the 525 should be a perfect cfm, I would have gone with that if I wouldn't have found this used 625 for a good price.
I'll have to look to see if I have pics of my kickdown before I pulled my motor.
Jon
 

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Discussion Starter #10
Thanks Jon, I am about to order and I'm not sure if I should order one with the Ford kick down, so any advice would be appreciated.

If I want fuel economy I guess I should order the Jr.?
 

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the road demon will still give great fuel economy I doubt there would be any difference if both set up properly, you can always jet it down a bit if needed. The secondary metering block is nice as you can change secondary jets, the jr has a metering plate with no jets. Hopefully you are using an aftermarket intake vs the stock one as you will see more power and economy.
 

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do your self a favor and get a weiand 8124 instead, the weiand is a way better intake than the performer, makes about 15 hp/tq over the 2121 performer, it is a computer designed intake and makes up for the performer shortcomings. Its kinda like an in between of the performer and rpm air gap but with no low end loss.
 

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MacIntyreMustang said:
Thanks Jon, I am about to order and I'm not sure if I should order one with the Ford kick down, so any advice would be appreciated.

If I want fuel economy I guess I should order the Jr.?
If you are running the automatic and it has something that attached directly to the carburetor then you'll want to order one with the kickdown lever. There are so many different rods and cables that were used by Ford over the years that you may have to tweak or modify the kickdown to line up. My Cyclone is a 69 and it had a whole other set up above the trans that I hadn't seen before instead of the metal rod that comes up and it may be similar to yours.On the Cyclone I didn't have to use the F part numbered carb because of this.
 

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The reason that it distinquishes the JR vs the standard one is the fact that the Road Demon does have the secondary block and can be jetted for a little better performance if needed.
 

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JonK said:
The Jr. has a single inlet vs the Demon double inlet/dbl. pumper I assume which lowers your economy. I used my Jr. to run the 1/8mi. in stock trim and it sure didn't stumble or limit my speed.
It sounds like you're confusing dual feed inlets and double pumpers. The Road Demon may have dual inlets for the fuel (one for each bowl) as well as duel metering blocks (a primary side and secondary side), but as a vacuum secondary carb it is still only a single pump carb. Having 2 fuel inlets has no affect on mpg, neither does 2 metering blocks. If anything, the more precise tuning capability of having a secondary metering block may make better mpg possible.

Neither of those features have anything to do with being a single pump or double pump carb, however double pump carbs tend to have lower mpg in normal stop and go driving because there's 2 accelerator pumps dumping fuel into the engine every time you step on the gas pedal instead of just the single pump that is used on the primary side of a vacuum secondary carb. Both the Jr and Road Demon are vac 2nd's, so they should both have very similar mpg capabilities with the specific tuning being the only major variable.

Theoretically, a single pump and double pump carb can get equal mpg if you keep your foot out of the pedal enough that the accelerator pump on secondary side of the carb doesn't get used, but in actual practice double pumpers generally do get lower mpg on the street (although I'm sure someone will chime in with the claim that their DP carb gives them great mpg). However, since both the Demon carbs discussed in this thread have vacuum secondaries and are not double pumpers, that's a moot point.
 

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Rickmaan said:
JonK said:
The Jr. has a single inlet vs the Demon double inlet/dbl. pumper I assume which lowers your economy. I used my Jr. to run the 1/8mi. in stock trim and it sure didn't stumble or limit my speed.
It sounds like you're confusing dual feed inlets and double pumpers. The Road Demon may have dual inlets for the fuel (one for each bowl) as well as duel metering blocks (a primary side and secondary side), but as a vacuum secondary carb it is still only a single pump carb. Having 2 fuel inlets has no affect on mpg, neither does 2 metering blocks. If anything, the more precise tuning capability of having a secondary metering block may make better mpg possible.

Neither of those features have anything to do with being a single pump or double pump carb, however double pump carbs tend to have lower mpg in normal stop and go driving because there's 2 accelerator pumps dumping fuel into the engine every time you step on the gas pedal instead of just the single pump that is used on the primary side of a vacuum secondary carb. Both the Jr and Road Demon are vac 2nd's, so they should both have very similar mpg capabilities with the specific tuning being the only major variable.

Theoretically, a single pump and double pump carb can get equal mpg if you keep your foot out of the pedal enough that the accelerator pump on secondary side of the carb doesn't get used, but in actual practice double pumpers generally do get lower mpg on the street (although I'm sure someone will chime in with the claim that their DP carb gives them great mpg). However, since both the Demon carbs discussed in this thread have vacuum secondaries and are not double pumpers, that's a moot point.
That would be correct and where the trans/converter or manual transmission is taken into account for vacuum secondary vs a mechanical one the combination will play somewhat of a factor in the fuel mileage as well but traditionally the vacuum secondary carbs will get better fuel mileage then the mechanical secondary ones also referred to as double pumpers.
 

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Discussion Starter #18
Thanks for the write up guys! Looks like I will get the Road Demon without the kick down. The kick down set up on my car is separate and does not attach to the carb. The Road Demon is a much better buy if it is more adjustable. The Jr. Is regular price around $300 I think, and the Road Demon is $378.

I drove a friend's 65 289 with a Weinand intake and it seemed to work great. So maybe that is the way to go for the intake.
 

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MacIntyreMustang said:
Thanks for the write up guys! Looks like I will get the Road Demon without the kick down. The kick down set up on my car is separate and does not attach to the carb. The Road Demon is a much better buy if it is more adjustable. The Jr. Is regular price around $300 I think, and the Road Demon is $378.

I drove a friend's 65 289 with a Weinand intake and it seemed to work great. So maybe that is the way to go for the intake.
Not a problem. If you haven't figured out already we are tech support for Demon Carburetion as it is a Barry Grant company so if you have an issue or any tuning questions once you get it on feel free to send us a pm.
 

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Rickmaan said:
JonK said:
The Jr. has a single inlet vs the Demon double inlet/dbl. pumper I assume which lowers your economy. I used my Jr. to run the 1/8mi. in stock trim and it sure didn't stumble or limit my speed.
It sounds like you're confusing dual feed inlets and double pumpers.
Rickmaan, you're absolutely correct, I mistakenly made the jump from double inlet to double pumper. I need to take more time with some of my replies. Thanks for pointing that out for me and the OP.

MacIntyre, let us know how it works out and which carb/intake you go with.
Jon
 
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