351w Idle problems
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Joined: Jan 2001
Posts: 56,966
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From: Virginia
I like the stock intakes, they are fine way to get a 4bbl on there cheap. But, you will need a spacer of some sort, you can see the black port to the right where the EGR was located, that will need to be blocked off. Also you can see to the left in the picture a smooth area with a large hole and two small holes on either side. That will need to be blocked off also. You can't lose with it being only $20, and if you stumble on a aluminum intake later, you can get that and swap it on.
Edelbrock has good literature with their carbs you can download it on their website. If you study it and really get into how it works, I do not see why you could not get that carb rebuilt. I am for the 4bbl swap.
As far as the EEC thing, I have forgotten that you have a EEC system on this engine. If you are going with the 4bbl carb, or any other non-stock carb, you wlll need to get rid of that distributor. Go ahead and buy one of those 1 wire HEI distributors and slap it on. The whole top of the engine will be different/rebuilt/new, the only thing left will be the basic mechanical part of the engine underneath. You can't run the EEC system with a non-stock carb and have it work correctly.
Edelbrock has good literature with their carbs you can download it on their website. If you study it and really get into how it works, I do not see why you could not get that carb rebuilt. I am for the 4bbl swap.
As far as the EEC thing, I have forgotten that you have a EEC system on this engine. If you are going with the 4bbl carb, or any other non-stock carb, you wlll need to get rid of that distributor. Go ahead and buy one of those 1 wire HEI distributors and slap it on. The whole top of the engine will be different/rebuilt/new, the only thing left will be the basic mechanical part of the engine underneath. You can't run the EEC system with a non-stock carb and have it work correctly.
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Joined: Jan 2001
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From: Virginia
It will look like this if it is not EEC.
Moderator
Joined: Jan 2001
Posts: 56,966
Likes: 2,728
From: Virginia
If you are talking about the round port with the two holes to the left of the carb pad in the picture above, that is not the choke heat riser, that is a spot for a vacuum operated door that opened or blocked the heat under the carb.
Everyone has different opinions on this, I will tell you mine. First, I would keep the exhaust running under the carb, some people completely block it off with block off gasket plates on the intake gaskets. My engine would not run correctly in the winter like this. The intake gasket set will come with shiny metal restrictor plates. I put these in both sides on both gaskets, and install it that way. It seems to give it enough heat in the winter to help it run, without overheating it in the summer time.
For that port on the left, I have never run the vacuum operated thing, I would not know what to hook it to if I did have it. What I would do is get a small flat piece of metal, and saw/file/carve myself out a plate that fits with two holes to line up with those holes in the intake. Put some high temp orange silicone under it and tighten it down so it will not leak exhaust.
I think I mentioned before, you will also need a carb spacer that will block off the EGR slot on the right side of the carb pad. You can see the black were the exhaust was coming up the port. You need a solid spacer that will block that port without burning up. I do not think I would use a phenolic spacer.
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Joined: Jan 2001
Posts: 56,966
Likes: 2,728
From: Virginia
P.S. You might want to investigate and see if you can plug the slot off with JB weld without plugging the passage below totally off. That might take some of the heat off the carb spacer and it's gasket.
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Cargo Master
Joined: Dec 2004
Posts: 3,362
Likes: 22
From: Florence, SC
Originally Posted by Franklin2
If you are talking about the round port with the two holes to the left of the carb pad in the picture above, that is not the choke heat riser, that is a spot for a vacuum operated door that opened or blocked the heat under the carb.
For that port on the left, I have never run the vacuum operated thing, I would not know what to hook it to if I did have it. What I would do is get a small flat piece of metal, and saw/file/carve myself out a plate that fits with two holes to line up with those holes in the intake. Put some high temp orange silicone under it and tighten it down so it will not leak exhaust.
I think I mentioned before, you will also need a carb spacer that will block off the EGR slot on the right side of the carb pad. You can see the black were the exhaust was coming up the port. You need a solid spacer that will block that port without burning up. I do not think I would use a phenolic spacer.
For that port on the left, I have never run the vacuum operated thing, I would not know what to hook it to if I did have it. What I would do is get a small flat piece of metal, and saw/file/carve myself out a plate that fits with two holes to line up with those holes in the intake. Put some high temp orange silicone under it and tighten it down so it will not leak exhaust.
I think I mentioned before, you will also need a carb spacer that will block off the EGR slot on the right side of the carb pad. You can see the black were the exhaust was coming up the port. You need a solid spacer that will block that port without burning up. I do not think I would use a phenolic spacer.
Originally Posted by Franklin2
P.S. You might want to investigate and see if you can plug the slot off with JB weld without plugging the passage below totally off. That might take some of the heat off the carb spacer and it's gasket.
Now I remember why I decided to go with an Edelbrock Performer intake. Other than the exhaust system, that is the *only* non-Ford part on my whole engine. Not only does it flow better, but it is MUCH lighter than the stock cast iron intake and you don't have to make the above modifications
.
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Mountain Pass
Joined: Mar 2018
Posts: 233
Likes: 2
From: Puyallup, WA
Well guys, I replaced the intake manifold gasket yesterday. There was an obvious tear on the gasket near the water channel nearest to the thermostat. I thought this thing had a leaky thermostat but it turns out this is likey where the fluid was coming from.
For now I decided not to go through with the 4bbl conversion. I still don't have all the parts I need.
I pulled off the intake and carb as one, but left the distributor in. I put penetrating spray on the bolts every day for a few days and the bolts came out super easy. Cleaned the mating surfaces on the heads, block, and intake very well. The gasket set I bought came with cork but the only one out of all of them that was shaped properly was the one on the front near the distributor. The others wouldn't go together in any combination for the back side so I just used a very thick bead of Permatex Ultra Black and used the supplied gaskets for the head to intake. I followed the instructions on the Permatex and didn't start the truck for 24 hours. New thermostat as well.
I then went through all the steps outlined above to get it turned properly. Warmed engine, Timing set to 10, mixture screws 2 turns out, mixture in until it started to change, then out 1/4 turn. Then the other side. Then I set the idle to about 750, it was still hunting a little but it was much better than before.
Then I went for the first drive. Right as I left it felt like I needed to adjust the idle a little higher as it was dying when coming to a stop in drive. The more I drove it around the more I noticed how much better it's running in general. It sounds a lot better driving around. I'm noticing less engine noise and it has a better exhaust note.
When I parked at the house the idle was high at about 850 stopped in drive, but when you put it in park it jumps up crazy high like 1200.
It still hunts around, but not as badly as it did before the new intake gaskets. I've capped off all unused ports on the vacuum tree, replaced hoses that looked bad, and pretty much every hose has a little pinch clamp on it holding it down. Unless it's leaking where the vacuum tree meets the intake I don't know where else it could be a vacuum leak.
I've also been trying to fix a cooling issue. Could hunting idle be attributed to that? I'm out of ideas.
For now I decided not to go through with the 4bbl conversion. I still don't have all the parts I need.
I pulled off the intake and carb as one, but left the distributor in. I put penetrating spray on the bolts every day for a few days and the bolts came out super easy. Cleaned the mating surfaces on the heads, block, and intake very well. The gasket set I bought came with cork but the only one out of all of them that was shaped properly was the one on the front near the distributor. The others wouldn't go together in any combination for the back side so I just used a very thick bead of Permatex Ultra Black and used the supplied gaskets for the head to intake. I followed the instructions on the Permatex and didn't start the truck for 24 hours. New thermostat as well.
I then went through all the steps outlined above to get it turned properly. Warmed engine, Timing set to 10, mixture screws 2 turns out, mixture in until it started to change, then out 1/4 turn. Then the other side. Then I set the idle to about 750, it was still hunting a little but it was much better than before.
Then I went for the first drive. Right as I left it felt like I needed to adjust the idle a little higher as it was dying when coming to a stop in drive. The more I drove it around the more I noticed how much better it's running in general. It sounds a lot better driving around. I'm noticing less engine noise and it has a better exhaust note.
When I parked at the house the idle was high at about 850 stopped in drive, but when you put it in park it jumps up crazy high like 1200.
It still hunts around, but not as badly as it did before the new intake gaskets. I've capped off all unused ports on the vacuum tree, replaced hoses that looked bad, and pretty much every hose has a little pinch clamp on it holding it down. Unless it's leaking where the vacuum tree meets the intake I don't know where else it could be a vacuum leak.
I've also been trying to fix a cooling issue. Could hunting idle be attributed to that? I'm out of ideas.
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Mountain Pass
Joined: Mar 2018
Posts: 233
Likes: 2
From: Puyallup, WA
I'm not sure. Before I left I'd already set the idle. It was about 750-800 in P and ended up being about 640-700 stopped in D. But the time I made it back it was much higher. The only thing I can think of is when the truck is just idling it doesn't get as hot as it does when I drive around, but when driving around it's still only pointed at the M and A in NORMAL on the temp gauge.
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Joined: Nov 2019
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I'm not sure. Before I left I'd already set the idle. It was about 750-800 in P and ended up being about 640-700 stopped in D. But the time I made it back it was much higher. The only thing I can think of is when the truck is just idling it doesn't get as hot as it does when I drive around, but when driving around it's still only pointed at the M and A in NORMAL on the temp gauge.
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