headers/Y-pipe help!?!

[90-k1500]

Hi guys, I'm new to the site and joined specifically to ask this question but there looks to be a wealth of knowledge on here and I am exited to explore more of the site! but for now I need some help with this...


I'm looking at getting short or mid length headers and a y-pipe but none of them seem to match up? All of the y-pipes I've found look like they only accept a donut gasket but most of the headers look like they are just flat at the collector, I found some headers with donut gaskets at the collectors but they have a 2.5" outlet and all the y-pipes are 3" inlets?
the headers I found with the donut gaskets were called m2 manifold exhaust headers, I found them on ebay
I'm new to headers but there not that much more than manifold and my manifolds/y-pipe are almost rotted through.
any help would be awesome!

btw My truck is a 1990 k1500 5.7L ext cab

 

[GMRedline]

I am a newbie here but I have been researching different exhaust setups for the past few months. When I decided to upgrade my exhaust, here is what I am going to do.

Buy a set of SS headers for an 88-95 1500. Maybe like these.

http://www.ebay.com/itm/SBC-Chevy-8...Parts_Accessories&hash=item5d4a5934b9&vxp=mtr

I will have to block of my EGR but who cares.

Then find some used Y or crossover pipes from a 2500. Here are some pics of a 1500 vs a 2500

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Replace the cats with some high flow ones.

http://www.ebay.com/itm/3-Thunderbolt-Catalytic-Converter-High-Flow-Stainless-Steel-/140941752250

Y them together into a single 3" pipe and run a 3" magnaflow 18" long resonator I already have from another project. If it's too loud, I will have room to add something after the resonator.

I "might" cut off the donut flanges on the headers and downpipes and use V-clamps instead.

http://www.siliconeintakes.com/prod...d=319&osCsid=7fe2254bc811a1232aba6e3d5e3478cd

I have had very good luck with V-band connections on other projects. But they had some extra cost.

Again, I am newb! lol

 

[GMRedline]

I missed your question donut flanges.

It "appears" you could run those M2 headers with the 2500 y/downpipes. I planned on getting mine from the junk yard.

The sizing of a exhaust system is very important. You want the largest diameter (best flowing) components closest to the engine where the exhaust gases are the hottest (most active) and require the most room for good flow. As the exhaust gases travel down the exhaust system they cool requiring less room for flow. The best exhaust systems <platform independent> "stepdown" in size from the engine to the exhaust tip.

It wouldn't make sense to use a header with a 2.5" outlet and run a 3" cat-back. At that point, your just making noise. (And that is what some people are looking for. So it's okay)

People on this platform don't really like the "shorty" headers as much as the mid-length or longtube. Most agree it is an upgrade to stock but don't flow as well as a mid-length or longtube. I think that is a true but I also believe it has to do with the fact that most shorty headers have that donut flange that goes down to 2.5" where as most mid-length and longtube headers have a 3" collector. So I think it is a combination of the design and the outlet.

Again, I am a newbie to this platform. All of my experience comes from a platform with 4 less cylinders where it is a lot harder to build a high performance AND nice sounding system. But I have spent a lot of time and money trying different setups with different results.

just my .02

 

[90-k1500]

Thanks for the reply first of all but I guess my main question is will a ypipe with a 3 inch inlet mount up properly to a header with a 2.5 inch outlet? not really worried about making power, I'm just replacing my leaky exhaust and thought why not go headers.

also will 3 inch headers mount properly to a 3 inch y-pipe even though the y pipe looks as though it needs a donut gasket and the headers don't have them?

another option I was looking at was flowtech mid length headers and their "matching" high flow y-pipe but these look like the same donut/no donut gasket problem?

 

[slippy3002]

I have shorty's from pacesetter and they are fine.

Sent from Robl@nd

 

[TylerZ281500]

I have shorty's from pacesetter and they are fine.

Sent from Robl@nd

i hate my pacesetters! i would beat the out of them if i had something to replace them with. tighten the bolts every few oil changes even with thread locker, then trying to force them to even get the bolts to line up holy crap! i hope there newere stuff is better cause im pretty sure these headers have been on here for awhile but geesh. end rant

 

[slippy3002]

i hate my pacesetters! i would beat the out of them if i had something to replace them with. tighten the bolts every few oil changes even with thread locker, then trying to force them to even get the bolts to line up holy crap! i hope there newere stuff is better cause im pretty sure these headers have been on here for awhile but geesh. end rant

on retightening the bolts, but you will have that any of them. That's why stock manifolds and the old factory headers were cast iron, it holds up under heat better.

Use the star style lock washers.

Sent from Robl@nd

 

[94 cheyenne]

ive got the flowtech short tubes on mine they were direct fit for my 94 though your #8 plug will be a little difficult to change