79 bronco 351m c6.
I have the cast stock manifold and a pretty good rear manifold oil leak. I have read about using a cherry picker to pull the manifold. I have the picker already.

I have a couple questions. Should I keep the stock intake or find an aluminum one? This is not for performance but maintenance. I wouldn't mind sometime in the next 12-24 months to make some performance upgrades.(I want to keep my 2150 carb)

2nd?... Local parts store ask do I want just the rtv stuff or new valley pan and sealant. Do I NEED a new valley pan or can not really answer until intake is liftted?

3rd?... I've read some time ago, about a plug/cover for the exhaust port coming into the intake. What are the ileffects of blocking that for both winter and summer use? This is a dd so being reliable all year is a must.

Any insight and help will be appreciated. Thanks Chris

 

Hey Chris.
I like aluminum, but it's not necessary and the old intake should still be able to seal, unless it's got another issue such as a crack, or gouged seal area from some previous work. Would not be the first time someone buggered something taking it off.
Never used a cherry picker to do that, but that sounds like it'll save a back or two! I should have thought of it!
If you're planning to do some mods later anyway, and don't mind spending the money now, I would probably go ahead and change the intake so you don't have to do it twice. I went with the Performer but have not fired it up yet, so can't tell you anything about it other than it's much lighter!

I've never had any trouble with any engine using the standard gaskets before, but in the case of my 400 after the machine work I remember my gasket went in really funky and squeezed out like no other I'd had. So I'm thinking of taking the intake back off and re-doing it entirely with sealer like so many do nowadays. I'm just resistant to change and contrary (and lazy?) so will probably leave it just to see if it leaks.
In fact, it's hard to find anyone that still recommends the end seals anymore. Everybody is on the silicone bandwagon. Probably for good reasons...

If you keep the EGR functional like I did, Edelbrock makes a nice 2bbl adapter with EGR (and one without) so you can do that too. I'm not sure how much efficiency you lose regarding the manifold and an adapter, but nothing wrong with wanting to use a stock carb on your engine. They were pretty darn good.
What climate do you live in? If it gets really cold in the winter I would not use the block-off plates. I think I did no mine, but here we don't worry about that strange thing called "winter" that most others have to deal with. Granted, if I go up into the mountains in the colder season, I might live to regret that. But it seemed reasonable for what use I expect to put my truck to.

Paul

 

I went with an edelbrock performer 400 dual plane intake and an edelbrock AVS thunder series truck carb. (650?) I did not want to give up my two barrel as it was rebuilt, but the performer intake had no provisions for the heat plate tube riser thing which leaked exhaust constantly anyway. I actually gained a bump in MPG with the 4 barrel due to the smaller primaries on the 4 barrel carb. This is on a severe duty work truck and DD, it gets below zero here for a good portion of the winter, I have had no problems whatsoever with cold starts with the electric choke even on the coldest days. As for the valley pan, I don't re-use them. I did once with a Cleveland years ago, and it wouldn't seal properly. I believe they are stamped with a slight contour around the intake ports that helps flatten and seal when torqued to spec. And, yes, a thick blast of RTV at either end vice using end seals seems to work best in the long run. Make sure everything is clean clean clean and don't skimp on it. Good luck.

 

Paul posts is pretty good.
As for the RTV and being pushed out that is not a bad thing and is pretty good thing. I like to pre-fit the intake less gaskets so I can check fitment and how thick the RVT should be.
If you don't know the gap and put a thick bead, let it skim up a little then install the intake and find a little gap or worst no gap, a lot of the RTV will be pushed out.
When I say "no gap" the intake could be sitting on the end seal area and leave a gap at the head area that gaskets will not seal that is why I like to "dry fit" intakes.

As for using the pan gasket or not here is something to think about. I will post up what we found on AMC v8's that also use a pan type intake gasket, Ford may OR may not be the same!
Think about it the pan is there for a reason, to keep hot oil off the bottom of the intake. This can lead to over heating the intake & carb and lead to fuel boiling, heat soak and hard start hot.

The other thing with the pan gasket and oil is it acts as a baffle. The AMC v8 motors has the PVC in the rear of the intake manifold and with out the pan gasket the PVC can suck up oil and out the tail pipe. It does this so little that you cant see if as smoke but will see the oil level go down and it did not do this before the intake change.
Also on the AMC intake there is another baffle, for PCV, riveted to the bottom. This needs to be moved over to the new aftermarket intake or again could have issues with the oil level dropping even using the pan intake gasket. This is where a dry fit with the pan gasket pays off as this baffle may hit the pan gasket and keep it from sitting right. The fix is to cut a hole in the pan for this baffle to fit thru so the intake can sit down all the way.

Also a hotter intake is not good for performance and that bring us to blocking of the cross over. It is there to help heat the intake when the motor is cold and this helps keep the gas as a vapor and not fall out of the air and make a puddle on the intake floor and cause other issues.
This cross over work with the valve between the head pipe and exh manifold, you have one yes? It is closed when motor is cold and this forces hot exh gas to go up thru the intake to heat it and then out.
If you run headers and no valve or have removed it you may have vary little or on hot exh going to the intake manifold when cold but once the motor is up to temp this exh. valve opens and little to no exh gases go to the intake manifold.
I don't think I have ever had a street car/truck with this blocked off so I cant say how much it is needed when it gets really cold out and yes I did live in CT for 50 years and it got cold. I do have it blocked off and use the pan gasket on my drag AMC car motor as I want to keep the intake as cold as I can for racing.
If me I think I would try and block it off as it is only when the motor is cold, little longer warm up maybe, once warm it should not be an issue.
Do you use an open air cleaner filter or stock air filter assy.? This can also play into how it runs when cold both outside temp and motor wise.

Just wanted to post food for thought on intake swaps and pan gaskets so you can pick what works best for you.
Good luck
Dave ----

ps: the motor hoist is sometimes used because the intake gets stuck to the block but I can see it being used for the weight, they are heavy!