Bronco Forum - Full Size Ford Bronco Forum banner
1 - 14 of 14 Posts

·
Registered
1979 bronco 351m
Joined
·
8 Posts
Discussion Starter · #1 ·
New here, I’ve read a lot through these forums and was looking for some help. I have a 79 bronco with a 351. Edelbrock intake and 1405 carb. All the emissions have been removed. I’m getting vaccum on the porter side reading the same as the manifold Vaccum. So then obviously after setting the timing and hooking the distributor back up the idle goes up to like 1000rpm and around 24BTDC. I bought the carburetor used just to throw on there and get it moved around. So my question is, should I just pull the carb and adjust the plates and start from there? Should I rebuild the carb? Will that help? Vaccum on both vaccum ports at idle is 24. I’ve checked for vaccum leaks and found none. Thanks in advance.

A little more about the bronco, my grandma bought it new in 79. She passed away in 2004 and last time it was on the road was 2002. Over the course of the past few years I would go down to her property and gradually work on it a little at a time. I got it running and driving on its own, enough to tow it to my house where I have room to slowly restore it.
Motor vehicle Automotive tire Hood Car Automotive design

Automotive parking light Tire Car Vehicle Wheel
 

·
Joisey don't smell funny
78 Bronco Custom, 460/ZF5, Sniper upgrade, 3G, dual batt
Joined
·
1,643 Posts
To start with, kudos to you on saving that 79. Don't give up on it. Please fill out your profile & such, it helps everyone help each other. (y)
For carb tuning, I went the round & round with them for a few years on my 78. Having to adjust the choke every spring/fall was really getting under my skin. So I went with Holley Sniper (blatant promotion there).
So having said that, check out these two links I have bookmarked from when I was playing with two Edle 4150's & a Holley style Summit carb.

First link is a forum post that explains ported vacuum vs manifold vacuum. A lot of people will argue which one is best, you just have to form your own opinion & what works best for you. I use manifold vacuum myself and find it works fine.
ported vs manifold vacuum

The second links are to a YouTube channel. Check out several of his videos as he explains and walks thru carb adjusting & timing vacuum, very informative.
carb tuning & timing
Ignition timing explained
Advance timing curve


Hope those help. Keep us posted on the progress!
 

·
Registered
1979 Bronco, 460 Police Interceptor 550HP, C6 Rock Crusher, Custom Ford 9", 1 Ton driveshafts!
Joined
·
149 Posts
We had to remove the ported vacuum line to the disty, then set the timing to 15 degrees advance. Then, for the 1st time, we could reduce the idle speed to the point that the ported vacuum was no longer at manifold vacuum. This occurs because the idle speed is too high / butterflies are open. Took us about an hour to figure it all out!
 

·
Registered
1979 bronco 351m
Joined
·
8 Posts
Discussion Starter · #4 ·
We had to remove the ported vacuum line to the disty, then set the timing to 15 degrees advance. Then, for the 1st time, we could reduce the idle speed to the point that the ported vacuum was no longer at manifold vacuum. This occurs because the idle speed is too high / butterflies are open. Took us about an hour to figure it all out!
Did you keep it at 15° for initial timing after? The sticker under my hood called for 4°BTDC at 500 RPM (non AC). I considered running it off manifold vaccum but tuning it to where I thought was appropriate it would die out every time I put it in gear unless it idled at 1000RPM.
 

·
Registered
1979 Bronco, 460 Police Interceptor 550HP, C6 Rock Crusher, Custom Ford 9", 1 Ton driveshafts!
Joined
·
149 Posts
Yes, kept at 15° initial timing with no vacuum line to the distly. Until we did that, always had too much vacuum on the ported side due to idle have to be set too high. Total advance is now 35° including vacuum and mechanical. And make sure your mechanical is working and NOT stuck!
 

·
Registered
82 XLT Lariat 351w, Edelbrock 1406 4bbl ,C6 auto, auto locking hubs ,33x10.5x15
Joined
·
5,567 Posts
I've had the Edelbrock 1406 on my 82 for almost 4 years. I live in northwest pa (and all the drastic climate change of living on lake Erie) and since getting the carb dialed in right when we first put it on we haven't had to touch it in ages until I recently had the timing adjusted and then it was just a little tweak.
But... Maybe this will help you
 

·
Moderator and Scrounger Extraordinaire
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
19,451 Posts
New here, I’ve read a lot through these forums and was looking for some help. I have a 79 bronco with a 351. Edelbrock intake and 1405 carb. All the emissions have been removed. I’m getting vaccum on the porter side reading the same as the manifold Vaccum. So then obviously after setting the timing and hooking the distributor back up the idle goes up to like 1000rpm and around 24BTDC. I bought the carburetor used just to throw on there and get it moved around. So my question is, should I just pull the carb and adjust the plates and start from there? Should I rebuild the carb? Will that help? Vaccum on both vaccum ports at idle is 24. I’ve checked for vaccum leaks and found none. Thanks in advance.

A little more about the bronco, my grandma bought it new in 79. She passed away in 2004 and last time it was on the road was 2002. Over the course of the past few years I would go down to her property and gradually work on it a little at a time. I got it running and driving on its own, enough to tow it to my house where I have room to slowly restore it. View attachment 202275
View attachment 202274
Wow! I got chills reading that then seeing that beautiful specimen painted in Electric Mucus green. Please snap a pic of both door tags for me. I wanna see the paint code. My 78 is painted in light jade.

BTW those rear sliding windows are a rare option. Be very careful removing them if you have to. Especially the seals.

As for the carb, good luck. My tiny bit of carb knowledge is for holley carbs.
 

·
Registered
95 5.8L MAF XLT, Hedman Shorties/MF SS Y & Muff, E4OD, Man hubs, KYB Quads, 31x10.5x15, 313K miles
Joined
·
1,903 Posts
If you want your carb to run as designed you should remove the carb and adjust the throttle blades to expose approx .060" of the transition slot and they should also cover the Ported vacuum orifice, I have more experience with Holleys but the theory is still the same. I'm sure if you do an online search you can find the exact procedures to follow to adjust the throttles in the bore. Then you will have 0" vacuum on the ported nipple and manifold vacuum on the manifold nipple. Then all will be the way things are supposed to be and you can adjust accordingly just try not to move the primary throttle blades or write down the number of turns on the idle speed screw that get the blades in the proper position in relation to the ports so you can always go back to ground 0. Good luck, hope I explained it clear enough!
If you need more info after all this I can help more if needed but this should get you in the ballpark.
BTW the only cost to you will be having to deal with a "Grumpy Old Man"...🧓
 

·
Registered
1979 bronco 351m
Joined
·
8 Posts
Discussion Starter · #9 ·
Wow! I got chills reading that then seeing that beautiful specimen painted in Electric Mucus green. Please snap a pic of both door tags for me. I wanna see the paint code. My 78 is painted in light jade.

BTW those rear sliding windows are a rare option. Be very careful removing them if you have to. Especially the seals.

As for the carb, good luck. My tiny bit of carb knowledge is for holley carbs.

Green Font Gas Number Motor vehicle
 

·
Moderator and Scrounger Extraordinaire
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
19,451 Posts

·
Moderator and Scrounger Extraordinaire
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
19,451 Posts
Thats the info i needed! Paint color is Bright Emerald.

Your bronco was made in the Michigan Truck plant for the Richmond (Virginia i suppose) area.

It had open 3.50 gears from the factory and had a rear axle weight rating of 3750 lbs. According to the axle code, you have manual steering with a non-tilt steering column.

It had a 3 speed automatic trans, likely a c6.

It had black and silver vinyl interior from the factory.

A Marti Report will show you all this and every option it was ordered with. It will show you what dealer ordered it and rarity statistics for paint, trim, etc. Its i think $55.
 

·
Moderator and Scrounger Extraordinaire
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
Joined
·
19,451 Posts
If you still have the factory carpet, the actual full ford build sheet was tapped to the drivers side floor under the carpet.
Build sheet in my 96 f350 was sandwiched between the seat foam and steel wire mesh support. Its hard to read and i cant really decipher what the stuff even means lol!
 
1 - 14 of 14 Posts
Top