HEADERS VS MANIFOLDS
Posted 21 September 2004 - 08:52 AM
There are good and bad points to using both types of exhaust systems. Manifolds last longer, normally have less exhaust leak problems, don't create the heat problems that headers do and fit into the engine compartment better than most header applications. There draw back has always been they do not produce the horsepower that headers can provide. Headers on the other hand don't have the life that manifolds do, they create more heat and noise than manifolds, they have more problems with exhaust leaks over there life time and they normally have issues with fitting well in the engine compartment. They do how ever create more horsepower and fuel mileage than stock manifolds do.
There maybe a third choice to check out! Ford did produce Hi-Po exhaust manifolds for small block Fords (C3OZ-9430-1) (289, 302, 351W) and they are being reproduced today at a price tag of around $250.00. They would offer all the good things that a manifold has to offer and would also add performance and mileage like a header. These types of manifolds would be far better then the stock units but they would not give you the all out performance that a header would provide. The only issue with using this manifold is the front H pipe. These vans never had this manifold as an option so there is no front H pipe to order to fit. You would end up have a good exhaust shop build you the H pipe to fit the van. And you have to make sure its an H pipe and not just two single exhaust pipes as the balance pipe that runs between the two header pipes is needed to make the exhaust work right on any Ford Motor application.
This is not the cheapest option to go with but it would provide a system that gives you the balance between both types of products giving you more or less the best of both worlds. John
Posted 21 September 2004 - 11:06 AM
Posted 22 September 2004 - 01:48 AM
I do not think the HiPo exhaust manifolds will fit. The problem is the engine crossmember will not let the exhaust manifold bolt in. I have a set of '69 4V 351W exhaust manifolds and I could not get them to fit into the '69 E220. It hits the engine crossmember. That's why I bought the headers. The 351W's are almost like the HiPo's but they have 2.5" flanges/collectors, compaired to the HiPo's 2" flange. I even have a set of factory '87 Mustang 5.0L headers and they did not fit. But on the up side, the 351W exhaust manifolds will fit my wife's '65 Mustang, but I have to change the motor mounts and frame mounts to '66 289 Mustang mounts. It raises the engine a half an inch and that half an inch is what is needed to make the 351W exhaust manifold fit. Also, since I have the Fuel Injection setup form the '87 Mustang, I was thinking of putting it onto the E220's 347ci engine, but I will have to rework the upper portion of the intake manifold. I think the throttle body gets into the engine cover. I don't know when I'll get around to this project, because I still want to spend time with the family and have fun with the little ones as they grow up. We'll number this project #35. But the good news is the Van Disc Brake Project is number 8. So, if all goes well, I might be able to begin working on it around New Years.
On the subject of 2" dual exhaust, I ran stock exhaust manifolds and a dual 2" system with H cross over, not much of an increase in power. I then went to headers and dual 2.5" with an H cross over, did not loss any bottom end torque and the top end pulled strong. But the dual 2.5" are too noisy (I can't believe I said that. I'm I getting old? When I was 16, I wanted it like a Top Fuel Dragster.). So I'm going to change it to a dual 2.25" system with an 'X' cross-over and 2.25" Dyno Max Hemi Super Turbo mufflers. I have this exact setup on my '68 Chevelle with a 383, it's quiet and streetable but it pulls hard (That BMW M5 was sure supprised a rusted out Chevelle stayed with him).
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Posted 22 September 2004 - 11:49 PM
I've looked at that for my 74 and if you look at around a 99 Explorer 5.0 intake it has a 90* bend in it. It looks like it would clear the doghouse, if nothing else it might need a minor bump, but nothing like the late 80's intake. Also, supposedly that intake is supposed to flow pretty good.
Also, since I have the Fuel Injection setup form the '87 Mustang, I was thinking of putting it onto the E220's 347ci engine, but I will have to rework the upper portion of the intake manifold. I think the throttle body gets into the engine cover.
Posted 23 September 2004 - 01:52 AM
'99 Explore 5.0L, I'm going to have to find one.
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Posted 23 September 2004 - 08:42 AM
Vic had talked about using 351W exhaust manifold over the HiPo manifolds. Yes they do have the flow properties of the HiPo manifolds but the problem they bring when used on the 289 / 302 blocks is they sit to low on the motor and get in the way of motor mounts and cross members. Remember the 351W is the odd ball windsor block and has a taller deck height than the 289-302 motors. That means the exhaust manifolds have to be longer to get the exhaust to exit around the same location a 302 or 289 motor would. When you use the 351W manifolds on the 289-302 motor applications using factory stock front ends it places the exhaust exit lower and in most cases gets in the way of cross members, steering linkages and motor mounts. For Performance applications were you would need to have a larger exhaust dia. or motor sizes like Vic's stoker 347 or a stock 351W these 351W manifolds would be a must if you were not going to put headers on. For most of you this is not the case and the HiPo manifolds, headers or even the stock manifolds with dual exhaust will work just fine as you are only looking to get a mild performance boost from the applications you already have. HiPo manifolds are a bolt in application on any small block Ford motor but the outlet flanges do come out at a different angle and it will need a different front H or Y pipe than a stock set of manifolds would use. Yes there are probably a few applications were it maybe a problem but the problems will come from shift or steering linkages not the motor mount or cross member. Again you may be able to over come those problem by how the front pipe is made. The HiPo manifolds would make a good middle choice for someone looking for mild performance applications and not having the problems that can come with headers. John
Posted 24 September 2004 - 01:40 AM
I'm not sure if the HiPo exhaust manifolds will clear the '69-'74 engine cross member. The engine cross member comes up close to the stock exhaust manifolds. The stock manifold drops down about 3.5 inches and then goes straight back. But the Driver Side HiPo's angles down around 15 or 20 degrees from horizontal as it goes back. I think the bottom of the drivers side exhaust manifold will hit the engine cross member at cylinder number six. I think the right exhaust manifold will have a better chance of clearing the engine cross member because, I think, it does not angle down as much as the left side, as it goes back. I have not tried fitting in a set of HiPo's, but now I want to give it a try to see if they will fit, but I do not have a set sitting around. I have always assumed they will not fit since the Drivers Side HiPo exhaust manifold is simular to one of the 351W exhaust manifolds, I forgot if it's the right or left side. But I do know one of the 351W's exhaust manifolds hit the cross member and the other side sticks to far out and gets into the floor.
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Posted 24 September 2004 - 08:40 AM
Does anyone have the ability to take pics of the drivers side exhaust manifold on there stock 68-74 289 / 302 van? I would also like a pic of the motor mount area on that side as well. I would like the pic to show the rear part were it passes over the cross member and motor mount. The only good way to take it would be from the under side of the van or with the dog house off the motor compartment. Just trying to get a better idea of what is or is not in the way if HiPo manifolds are used. Vic points out that the driverside HiPo manifold has a more downward angle after it goes by the second exhaust port. This still should not be an issue with the motor mount as the mounting bolts on the block for the engine mount are in the same location on a car or truck. But it could be an issue based on how wide your crossmember is or if it is more offset to the rear than a car application. This request is for anyone that has the time to do it and is no big rush. Based on the conversation we have been having on this subject I figured it would be something to check into incase anyone decides to do this upgrade. Thanks for your help, John
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