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Author
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Topic: Headers or OE manifolds?
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Ryan Wilke
Gearhead Posts: 3237
From: Stanton, Michigan, zip 48888
Registered: Oct 2000
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posted 10-20-2006 06:34 PM
 
At what point are headers a performance benefit to an engine over the OE exhaust manifolds: Are headers only better at the higher rpm levels (say over 4000rpms)? When used for heavy work? or ? The subject F100 truck is equipped with a fairly stock FE 390" and 4-speed (T-18). It does my towing chores - primarily pulling my 3300# racecar on an open, twin-axle car hauler/trailer - but I also tow/use the trailer to move firewood, pallets of shingles/salt etc. maybe once a month. It rarely ever sees rpms over the 3000 mark. It does, however, breath heavy when I've got 5,000lbs on my trailer. Probably since the truck sits for a week or two at a time, is the reason why the damn headers have rusted out AGAIN!!! GRRRrrrr!  So.... I'm wondering maybe I should locate & bolt on some OE cast-iron exhaust manifolds that'll LAST longer than 4 years! I suspect if I did make the switch, I'd need to re-adjust my Holley 4bbl carb; but that's no biggie....... Thanks in advance for any of your thoughts/opinions, Ryan 
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Rory McNeil
Gearhead Posts: 1889
From: Surrey, B.C. Canada
Registered: Nov 2000
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posted 10-20-2006 11:10 PM
I`d stay with headers. I haul my race cars with a 1974 F350 dually ramp truck, with a 1976 390 and a NP435 4speed,& Dana 70 with 4.10`s. With a car on the back, and the storage boxes full of fuel, tools, floor jack etc, it`s usually between 10,200-11,700lbs.My 390 is basically stock, 8.5 compression, "RV"type cam, iron 4 barrel intake with a 450 cfm Holley, and a set of headers with 2 1/2" dual exhaust. Previously I ran the stock cast iron exhaust manifolds, which are very restrictive, which is likely why I had 3 of them crack in a 3 year period. I finally get fed up, and installed a set of Hedman full length headers in 1991. Man, what a differance! Noticably better power, from idle all the way up. I supose the gas mileage also improved some, but I don`t keep track of such things, it`s too depressing! The same Hedmans were on from 1991, until this summer, when I did a bunch of work to the truck (rebuilt steering box & rag joint, radius arm bushings, shocks, brakes, front air bags,starter, and a new dual exh.system) The old Hedmans had never given me any problems, but since they were 15 years old, I figure I may as well replace them since I had the drivers side out to change the steering box anyhow. Upon inspection, they still looked pretty solid, and likely were still good for a few more years. The new headers are Flow Techs,(nobody local had the Hedmans in stock), and they seem ok so far, although I did have to position the collector flange ring just right to clear the clutch throw out fork. My truck is used almost exclusively for getting to the track, normally about 45 minutes each way, although it has been on some 12 hour treks, and the ocassional trip to the dump, or to move a car for a friend. Otherwise it sits for weeks at a time, and from Oct. till March. Maybe I`m lucky, I`ve had the exhaust system behind the headers rot out, but never the headers themselves. I`ll never go back to exhaust manifolds.
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78 Fairmont 428 4 speed [email protected] 1.32 60 foot
80 Fairmont 302 5 speed 12.8@105mph
85 Mustang NHRA M/Stock 302 5speed. [email protected] 1.63 60 foot
59 Meteor (Canadian Ford) 2 dr sedan 332, auto
74 F350 ramp truck 390 4spd
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Ryan Wilke
Gearhead Posts: 3237
From: Stanton, Michigan, zip 48888
Registered: Oct 2000
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posted 10-21-2006 12:24 AM
quote:
Originally posted by Rory McNeil:
Previously I ran the stock cast iron exhaust manifolds, which are very restrictive, which is likely why I had 3 of them crack in a 3 year period.>>> I never considered that the cast manifolds might crack, but I should of, cause I KNOW they do.  And yeah, they are very restrictive...
The new headers are Flow Techs,(nobody local had the Hedmans in stock), and they seem ok...
>>> I was also looking at FlowTechs; 1.75" primaries and 3" collectors. Jegs sell 'em for $123. Hedman's are $150. OE manifolds can be had for about $70.
Thanks for sharing your experience & advice, Rory!   Ryan
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Ryan Wilke
Gearhead Posts: 3237
From: Stanton, Michigan, zip 48888
Registered: Oct 2000
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posted 10-21-2006 12:30 AM
Rory, How do ya like that 450cfm Holley on there? ...I'm running an ol' 780cfm VS Holley on a C6AE iron 4bl manifold and a PI-clone cam. The 390" seems to like it better than the 600 VS Holley that I had on it previously...
Ryan
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Rory McNeil
Gearhead Posts: 1889
From: Surrey, B.C. Canada
Registered: Nov 2000
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posted 10-21-2006 01:33 AM
The Holley 450 is nice and crisp, I had a stripped float bowl screw hole that required a Heli coil, and I never seemed to get around to fixing it, so I had an Edelbrock Carter style carb on the truck for a while. It was a 600cfm, #1406, but the little Holley runs soooo much nicer. I finally fixed the Holley a few months ago, and when I put it back on, it was so much more responsive, especially off idle, and part throttle. And for those Holley haters who think that they require constant "tinkering", I rebuilt this carb back in 1991, and never had to mess with it until last year when it sucked up some contaminated gas from my auxilary gas tank, which had water in it. It was after I removed the pri. float bowl to clean out the crud that the screw stripped. Since I normally don`t take my trucks 390 much over about 3000 rpm in normal driving, and maybe 4500 max wide open, I think that the 450 carb is sufficent. My truck weighs 6700 lbs empty, but doesn`t see much use without a load on it. It ain`t no race car.------------------
78 Fairmont 428 4 speed [email protected] 1.32 60 foot
80 Fairmont 302 5 speed 12.8@105mph
85 Mustang NHRA M/Stock 302 5speed. [email protected] 1.63 60 foot
59 Meteor (Canadian Ford) 2 dr sedan 332, auto
74 F350 ramp truck 390 4spd
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Ryan Wilke
Gearhead Posts: 3237
From: Stanton, Michigan, zip 48888
Registered: Oct 2000
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posted 10-21-2006 09:41 AM
Thanks again for sharing, Rory! Man, if you're normally moving 10-12K lbs. with your 390, then what I'm asking of my 390 to move is like a walk in the park for it! Of course, I learned early in life that it isn't the engine that determines what "work" can be done, it's the gearing package that's bolted to it. My first truck was a '63 F100 with only a 223" 6-cyl; but it had the T-18 4speed. I quickly learned why they call 1st gear a 'creeper' gear -- 1st gear is a whopping 6.32 ratio! (I know you know what I mean, since you're running a NP435, with a 6.69 1st gear). Heck, if I moved more than a truck length before shifting to 2nd, that 6cyl was revving big-time (even with the 17.5" rims/tires)! Even the T-18s 2nd gear is also sizable @ a 3.09 ratio, couple those gears with the 4.11 rearend gears...I would joke about, "I can pull stumps or climb trees given the traction"! I'd call it my, "Half Breed, 1/2 tractor & 1/2 truck". Ok, enough reminiscing for me,,,, I'd still luv to see a pic or three of your hauler, Rory! (I know, he's not pretty; but he's one 'tuff nut' that gets the job done!)
Later,,,, Ryan P.S.
Maybe I should simply drop by your place (!) with a cold 12-pak in hand & then you could then introduce me to your hauler in person! 
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Poes Fords
Gearhead Posts: 178
From: Medford, OR USA
Registered: Oct 2004
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posted 10-21-2006 11:39 AM
I have personally have been wanting to go back to exhaust manifolds on my 77 f-150. I love the power my headers give my 460. I would never think of this swap, but I have broke one header, and have never been able to make them seal . They are the Sanderson shorty style. They weren't made to fit my truck, but a notch to the left side engine tower and they fit like a glove. I have tried everything to make them seal, and I think the right side one has a crack in it now. Sounds like a dam% locomotive when it's cold . I built the 460 and ran the exhaust manifolds till I got the funds. Then I put the headers on, and it was instantly noticeable. It would crack your head back when you mashed the throttle. Sorry to ramble on, but if I found a set that fit and were leak free it would be headers all the way. I am just frustrated with my situation. Jason.------------------
1964 Falcon 289, toploader 4 speed, 9 inch 4.11's locker
1977 Ford F-150 swb 4x4, 460 4 speed.
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Dad Vishus
Gearhead Posts: 1153
From: Moscow, Iowa, USA
Registered: Dec 2001
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posted 10-21-2006 10:26 PM
I have been using headers on tow vehicles for years and would never switch back to iron manifolds.The last 2 were the 85 E350 we used for several years and last was the 84 class C motorhome I have now. Both were 460s. As I recall, both header sets were fairly cheap Hedmans. Fit was easy and they are both still in service. They both have a 3 inch custom bent up single exhaust system with a 3 inch RV style (huge) muffler. Quiet and efficient. Singles last longer too as they dry out better when run.
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Ryan Wilke
Gearhead Posts: 3237
From: Stanton, Michigan, zip 48888
Registered: Oct 2000
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posted 10-21-2006 10:35 PM
Ok, Fellas,,,,,, you've convinced me.
I'll get another set of headers.It's all good,,,,,,, Have a GREAT DAY! Ryan
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Rory McNeil
Gearhead Posts: 1889
From: Surrey, B.C. Canada
Registered: Nov 2000
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posted 10-23-2006 01:25 AM
Jason,why don`t you just buy the proper headers? There should be no problem finding name brand headers for a Ford pickup with a 460. ------------------
78 Fairmont 428 4 speed [email protected] 1.32 60 foot
80 Fairmont 302 5 speed 12.8@105mph
85 Mustang NHRA M/Stock 302 5speed. [email protected] 1.63 60 foot
59 Meteor (Canadian Ford) 2 dr sedan 332, auto
74 F350 ramp truck 390 4spd
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