im sure this has been beat to death...but headers or manifolds?

[k5-newbie]

I have a stock 350 tbi in my blazer now and I had to cut the exhaust off to fit my turbo 400 crossmember so now I need to have my exhaust re-run. I have a set of headers that will fit my blazer hanging on the wall in my shop and am debating rather to put them on or stick with the manifolds. I have headers on everything I own and know what a headache they can be. I am gonna use my blazer for mostly rocks and hill climbs not really any high rpm stuff.

The only reason i im asking opinions is that I am at a point where it would make sense that if im gonna install them, now is the time.

 

[Emmettology 101]

I say stick with the manifolds. After having my truck for 3 years, I have had one set completely rust apart and another set on its way out. The newest set I had completely cleaned up before installeing(yes they were brand new) and coated them with 1500* paint. I used quite a bit of it hoping the more the merrier. I put these on back in July or August. They already dont have any paint on them and are rusting. Actually, the paint burnt off within a few weeks.
Granted I've never had them leak at the gaskets because I used good ones, but I think I would rather sacrifice some HP and run manifolds.

But thats my .02 cents...

 

[dyeager535]

If they are long tube, run them. You know what you are getting into, "free" power is always good.

 

[Z3PR]

There is no question that Headers will out preform stock exhaust manifolds. The problem some people experence with headers usely comes from cheap headers. I am willing too spend more for the high quality. The high quality products normally fit better and last longer. You buy a $79 set of headers from JC Withey don't expect they'll be trouble free for life.

 

[R72K5]

headers will outperform but they will rot out badly esepcialyl all around collectors, and usually always have leak issues at the cylinder head, and manifolds usually always sound just as good or even better than headers do, with dual pipes,

its extremely hard to tell just by listening to a dual exhaust chevy whether its header or manifold, i have guessed some wrong and i have been around and heard BILLIONS of chevies, some manifold rigs have fooled me,
if engine is mostly stock, then id stick with manifolds, to save alot of trouble later, maybe port them a little in the runner openings(englarge and remove the bumps in there, only takes 10 or less minutes to port all that on each manifold with air powered drill and common tapered steel bit, and around the outlet ID too, and plane them at machine shop to make sure they are straight as can be



good luck

 

[dyeager535]

You guys that speak of headers rotting out quickly are from places that use tons of salt.

My friend has a pair of Edelbrock painted headers on his daily driver Monte Carlo that have been there over 5 years, and haven't given him an OUNCE of trouble.

Yes, cheaply made headers will rot out, but not all headers are made cheaply.

 

[TorkDSR]

melted wires, melted speedo cable, atf fire, toasted fingers, spark plug interference.

if i had the exhaust set up for manifolds, i would have left them on

but the weight savings is nicer than the performance gains imho

 

[originalspanksta]

headers are more prone to leaking, and seem to always get in close proximity to the passenger side spring shackle. they also hang much lower than manifolds, making exhaust harder to tuck up. I had headers on the previous version of my blazer, and while i liked the power, i really think they caused more problems than benefits. i will be leaving the stock manifolds on my new truck and just build the exhaust to be pretty free-flowing from there. less to worry about, more clearance= better in my book.

 

[mxfireman]

There is no question that Headers will out preform stock exhaust manifolds. The problem some people experence with headers usely comes from cheap headers. I am willing too spend more for the high quality. The high quality products normally fit better and last longer. You buy a $79 set of headers from JC Withey don't expect they'll be trouble free for life.

I agree, spend a little extra on good gaskets and maybee the locking exhaust manifold bolts and our likely to have less problems. I had problems with mine all the time and went to copper gaskets and haven't had any problems in over a year.

 

[pvfjr]

I agree with the salt theory, never seen that problem myself. I have had the privelage of having those stupid freakin studs being stripped, the threads looked like they just burned off. They were impossible to replace too! Snapped right off. Ever priced a set of manifolds when you didn't have time to scrounge around? Would make you sick. It's nice to know that there's just normal everyday bolts at my collector now. I have less leaks now than ever before.

 

[dyeager535]

melted wires

Poor installation. BTDT, manifolds will burn wires as well. Keep them away from hot metal, they are fine.

melted speedo cable

Poor installation. Melted mine on the exhaust while I had manifolds.

atf fire

Is why GM didn't use rubber for flammable fluid lines. Had a near miss when my rubber tranny cooler line popped and doused the exhaust manifold in ATF...couldn't see from all the smoke. One more reason I don't have an automatic in my truck.

toasted fingers

Manifolds don't get hot enogh to burn you? Headers will cool off faster than manifolds.

spark plug interference

Good headers don't have this issue. #5 is my lone problem, but I can get my hand and a wrench in there. Just don't use a socket. Besides, how often are people changing their plugs??

headers are more prone to leaking

The only reason my headers leak is because there are no locknuts on the collector bolts. Comes loose with prolonged dirt road driving. I'm going to fix that pretty easily with another nut on each bolt.

The only negatives cited I see with any validity (short of rust concerns in those areas that it is a real problem, then again the truck is rotting just as fast as the exhaust at that point ) are that SOME long tube headers hang down enough to reduce clearance somewhat, although that depends on your intended truck use, my t-case hangs down much more than the header collector, and shackle interference. Both of those apply to my set of headers, BUT there is no excuse for those problems on our trucks to blame the manufacturer(s).

I called Hedman on the shackle clearance issue, but they weren't real helpful. Factory tolerances I guess could be cited with some basis in fact. With a little force you can bend them away enough to clear the shackle/bolt though. (even though you shouldn't have to)

 

[Emmettology 101]

I called Hedman on the shackle clearance issue, but they weren't real helpful. Factory tolerances I guess could be cited with some basis in fact. With a little force you can bend them away enough to clear the shackle/bolt though. (even though you shouldn't have to)

Granted I do live in a "salty" area.. But the headers I currently have are Hedmans. All my paint is gone... They were just installed last July or August. Not they are all rusty. This truck was only drivin on a snowy road once this winter(steering issues)....

Also, had to change my plugs about a month ago..... I could only get to (4). The others were blocked by the header so I had to remove them to get the plugs out. Actually just unbolt them and pull them away from the head. Luckily I used good Percy Alum gaskets with the graphite inserts that are reuseable.

 

[dyeager535]

Here's my application number:69890. (Elites) Hedman told me they were wrong for my '86, I assume AIR or somesuch. Whatever, they fit and they are for a truck.

I broke my engine in on manifolds, but apparently didn't wait long enough. Bolted the headers on and they started to glow. Figured the coating would come right off. About six months later (now) the area that got super hot looks perfectly fine which is bizarre, yet the collector area is "covered" with rust(?)... not something that I can just pick off. I'm unsure if this is baked on mud/clay/whatever, or if it is the beginning of rust. It really isn't spreading, and it's only on the lower section that would have seen the most dirt and what not offroad, so I can't say what is going on there. Whatever their coating is hasn't come off (except where the shackle bolts rubbed) but yours are painted.

My plug access is so good I was amazed. I KNOW the horror stories about plug access, and so I expected them. Like I said though, number 5 is the ONLY one that causes me issues. All the others are super easy and can be reached with a deepwell socket.

I'm using the stock Fel-Pro exhaust manifold gaskets as mentioned in another thread. Working great so far, and no locking header bolts either.

 

[Emmettology 101]

Ya, with these gaskets I am using(they're either Percy's or Earl's) I use only regular bolts and have not had leaks....

My new headers were put on an engine with about 30K miles. So it was broke in.... BUt maybe my Trick Flow heads have something to do with plug access..

And yes, I got the cheapies and not the Elites. Got these on Summit clearance table for $35! Even was the right part #! Woohoo!

 

[dyeager535]

So are the heads then angle plug? If so I can imagine that makes things eminiently more interesting.

The way I look at it for headers is like this: if you pay a little bit of money for them, and they last a few years, great. You knew they were going to fail fairly quickly, but you gained power all the while and they can always be replaced.

If you pay a BUNCH of money for headers, like stainless, you should never have a problem with them rotting out, but the initial cost is the tradeoff.

I think mid-price range headers are a waste...coatings don't seem to stick real well, (not like stainless!! hah) and they will still rot out from the inside. Unless the fit is EXACTLY what you want, I can't see paying $100 more for a set of headers that are going to perhaps last just slightly longer than your painted ones. I think mine run $150 from summit (ripped off locally though of course) so at that price, I'd say around 5 years of life or so I'd be happy with the cost. That's 20 years (4 $150 replacements) to spend the $600 that I think stainless headers run.