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Hello, I have a 79 F250 with a 460. I want to install dual exhaust replacing the single exhaust with the converter.
What are the pros and cons of headers vs manifolds. I should add that the 460 is all stock with no upgrades.
Thanks in advance for any help.
Headers offer a slight increase in performance, in a stock pickup 460 it's doubtful you'd notice it.
Headers offer more leaks, engine bay heat and often fried starters. they have the added advantage of frustrating clearance issues and jigsaw puzzle fit on some vehicles as well.
I have headers on some of my rigs. the 428CJ in my highboy has them. I don't know why I did it.
If you do go with headers the Remflex gaskets are the only way to go.
That is pretty good and true recommendations... 460s have exhaust handicaps all the way around, Not that when I drive my 460 powered f350 I am concerned about gas, but gas mileage has improved across the board with headers, so keep in mind that how many miles will you have to drive in a 460 to save enough gas to buy a starter (and flywheel/flex plate if the failed starter kills that on its way out) to justify.... likely more than the life of the engine will tolerate, Leaks can be problematic, but not always. Depends on several factors there however just remember that a leak at the port will often take out the plug wire by blowing fire directly at it too, headers are good for moderatly built engines that need more flow and tend to peak out at higher rpm, not a large increase at stock levels, likely not worth the headaches unless you are planning a long term build of higher than stock level.
Pro:
Look cool, especially if power coated/chromed/nickel plated ='s $$$
Makes the truck sound like a powerhouse to the ears. Stock motor no REAL HP increase.
Depending on application you can run the rest of the exhaust cheaper and turn out in front of rear tires.
Con: X2 on all he said above. (starter cage) on long tube, so have to remove header to swap out starter, back to maybe break a bolt...again. Extra heat in eng compartment. Any loose wire touch the headers burned up wire. Have to retoute brake lines from master cylinder down to frame.
You risk breaking a bunch of exhaust manifold bolts off in the heads when you try to remove them.
You manage to break just a few and either drill out, tap and use new bolts. Or you have to use heli-coils. Can you do all that with the heads installed. PITA
They can be prone to leaks, resulting in having to buy Remflex alum crush gaskets.
Most rust out was faster that standard exhaust cast iron manifolds, unless coated.
Inside the frame rail exit headers and if the truck is 2wd you might have to contend with where they exit and collect. Might be right in front of the trans cross member. Better have a good exhaust shop on speed dial.
4wd inside the frame rail exit, have to contend with the front d/s clearance and getting around the xfer case. Then both pipes are on the passenger side of the truck.
When I had hedders and dual exhaust installed on my '79 F-260 with a 400 it really
didn't increase the power but it sure sounded a lot better and I'd do it again.
I was told a long time ago that it takes at least a 10% increase for you to feel it in the seat of your pants.
Thanks for all the reply's. Seems like the pros out way the cons. Part of my reason for asking is that the previous owner remove all the pollution control, so on the passenger side manifold, there is a large opening on the manifold that is assume went to the air cleaner. So I want to remove that side anyway to install a manifold without the opening. I'll try to post a pic of this.
Removing might be a headache as the bolts are rusty.
Yup just a sheet metal shield around the manifold to direct heat to the air filter housing when it's cold out. It would normally have a flexible metal tube going up to the air filter housing. There's no functional reason to block it or remove it, it doesn't really do anything. Most of them rotted away and fell off a long time ago.
With headers you get what you pay for. Generally the higher priced stuff has thicker flanges and more attention to the fit. I'd also suggest either ceramic coating or just heat wrap if you live in a dry climate.
Yup just a sheet metal shield around the manifold to direct heat to the air filter housing when it's cold out. It would normally have a flexible metal tube going up to the air filter housing. There's no functional reason to block it or remove it, it doesn't really do anything. Most of them rotted away and fell off a long time ago.
With headers you get what you pay for. Generally the higher priced stuff has thicker flanges and more attention to the fit. I'd also suggest either ceramic coating or just heat wrap if you live in a dry climate.
If you live in florida probably correct. Here in colorado at MY house We had single digit temperatures from october until march. some single digit above 0*f and some below 0*f that is october-november-december-january-february-march, 6 months of near 0* weather. My welding truck in the mornings would start and run a few minutes to be warm and defrosted, my other 1978 f250 with a 400 would run almost 15 minutes until it was defrosted. The difference is the welding truck has the functioning flapper in the air cleaner sucking warm air from the exhaust manifold, the other one does not have that, and the other one has a fan clutch, (clutch fan) supposedly allowing slip to warm up while welding truck has direct fan, so DOES NOTHING may not be entirely accurate folks. just food for thought. the fuel used on warm up everyday may be worth repairing that system if you need it to defrost.
The round part that the flex tube attached to and goes up to the air filter, is part of the heat shield that attached to the cast iron exhaust manifold. It is a separate part. part # 9A602 and 9A603
it is a seperate piece of sheet metal maybe called a heat stove or a hot air duct or a intake air heater system, it is not part of the manifold, all it is is a duct that pulls air into the intake from the manifold warmed by the exhaust until there is a temperature increase inside the air filter housing then the flapper opens to normal air and if extremely cold the flapper might cycle back to warm air. your opinion and unless you operate in a lower temperature climate, the system is negligible. In the last year at my house I have seen temperatures from -10* below zero to 105* above, likely the most extreme climate variations almost anywhere, I loke my heater to work and my air conditioner to work.
