Its about time for me to take care of the headers and exhaust on my 91 z28. The previous owner had it set up pretty lame, stock manifolds (lol), deleted cats (no emmesions), single 3 inch pipe (nice pipe), and a blown out flowmaster muffler (garbage). The car is a L98 with a Vortech S-Trim V1 blower. After my next round of mods I'm expecting around 500 fwhp, so I need the exhaust to support that power. The car is also slammed (adjustable height) so I'm limited to shorty headers for clearance reasons. I dont care about emmesions so EGR and the CATS are going byebye. Can anyone recommend what headers and muffler I should go with? I'm expecting to spend around $600-$800 for the parts, am I crazy? Should I keep the single 3" pipe, or ditch the whole thing and experiment with true duals? Whats the max HP a single 3" pipe can support? Thanks!!

 

Well if you are limited to shorties I would say Hooker 2055's with no cat and any 3 inch catback of your choice. If you were to go longtubes you would have much more choices, but for shorties the hookers into a straight pipe with just about any catback will be the best setup. I might even put a cutout where the cat once was.

 

A set of non coated 1 3/4" single cat SLP's can still be had new for about 380 plus shipping, and a loudmouth is about 320 i believe. there ya go just need a "test pipe" and "cat adapter" along with a bend to adapt to the loudmouth

 

I would get some 1 3/4 primaries....with 500 plus horsepower.

If you can still get SLP's w/out air tubes then I would do that, followed by a Borla adjustable exhaust, but then you are spending well over 1,000 bucks.

I think a 3 inch pipe should be big enough for ya, it is on my 95' trans am which is pushing 460 hp N/A.

My next suggestion if cost is a factor ( which it is) is to get a Dynomax Ultra Flo setup. I have a regular aluminized setup on the 91' but with a stainless muffler in place of the old one ( was a super turbo) and it's freakin awesome. Sounds like a speed boat, kinda like my Borla but not as loud.

The Ultra flo mufflers flow THE BEST out of all the choices for thirdgen crossflow styles, so keep that in mind. The 3 inch version flows over 900 cfm.

 

With the SLP headers it really makes no sense to go 1 3/4 inch primary tube when the y pipe is only 2 1/4 inches into 3 inch anyways. Why on earth would you put dual 2 1/4 inch pipes on a car that requires 1 3/4 inch primaries. Makes no sense. Besides, the primaries are so short on shorty headers that the difference between 1 3/4 and 1 5/8 really wont be much. To tell you the truth, you will be choking the motor with either of those choices and a set of hooker longtubes into a mufflex 3.5 y pipe would be a good setup for that. Seeing as how you are limited to shorties though the Hooker 2055's seem to be the best choice for just about anything including you.

 

Thanks for the replies!! I appreciate the help! I wish I could do the longtubes too but I'm afraid the longtubes would be hitting the ground alot. I've seen longtubes on some other cars and even at stock height they get close to speedbumps. So basically, the biggest shorty headers I can get are 1 and 3/4th's but the provided y-pipe would be a restriction? How about if I ran the 1 3/4th's shorties, a 3" y-pipe, a 3" test/offroad pipe (no cat), the 3" single all the way back, and then a nice 3" Cat-Back system? Would the headers be the restriction at that point?

My next set of mods should put me around 500 fwhp @ 6,000 rpm. I think the above setup would be a nice match ... but I'm not so sure about my future setup. I do plan to ditch the 350 sometime next year and swap in a 400 block (and boost it!). At that point its very possible I could be pushing over 500 hp. So now I'm wondering if the shorty headers might be a bad choice in the long run. Good for clearance, but possibly bad for future plans. What do you guys think?

 

I think a set of hooker regular comp shorties or the SLP 1 3/4 inch headers with a custom y pipe would be a nice setup for that car and provide plenty of ground clearance if done right. I might go even bigger than 3 inch for that car and a mufflex catback. That would be a sweet setup.

 

HOW SLAMMED is it.

My 92 Is lowered with hotckise springs and my Hooker LTs fit just fine and have clearance

 

I'm using 1/2 height springs and adjustable weight jacks. At full lock up its the stock height, at full lock down the tires (its on 18's) are resting on the wheelwells (basically as low as you can go without cutting fender). I need to do some measuring to find out exactly how much its dropped for street driving (I can only estimate right now). I do have the option of raising it up for street driving but I really like the slammed stance. Hard choice for me.

 

Cool

 

Just to keep you guys updated on my progress ... I've decided to go with the SLP 1 and 3/4 inch primaries, then a MAC 3" Y pipe, then an electronic exhaust cutout, then through a 3 inch off road pipe (no cats), and then 3" single pipe to the back. Still undecided on what muffler/catback to use, but for now I'm just gonna focus on the headers, Y pipe and cutout. So I picked up the MAC 3" Y pipe last night. Its a real nice Y pipe!! I got the Y pipe and a stock replacement flowmaster muffler (which I dont plan to use) for $150. I'm thinking I'll save the muffler for a later project (S10 maybe?). So my next step is to get the headers (w/o air tubes) and the cutout. Then my motor can finally breathe!!

 

I am going thru the same process with my 84 right now. I went with SLP 1-3/4 without AIR. Getting a custom built 2-1/2 to a 3-1/2 Y-pipe with a flowmaster 2-1/2 to 3-/12 Y collector that will go to a 3-1/2 "I" pipe with a Dynatech 3-1/2 straight thru race muffler (6 inch length) with a tuneable Dynatech exhaust cone inside the exhaust pipe after the muffler just before the turndown that will end at the back axle.

 

Many LS1 guys put over 400 to the wheels with their 3" exhaust. I think 450 is about the limit before it starts to become a hinderance. Longtubes would be the best for your application but because your car is so low you have to go the shorty route. However fear not. I have seen majorly built cars switch from shorties to longtubes and only pic up between 5 and 15 hp. Now that sounds like a lot but when you are making 500 it is okay to sacrifice in the name of clearance.

 

I'm not a great horsepower guy but I do know alot about Exhaust, and since your car is slammed and there is a point that u may be only limited to shorties....I would imagine if u would like to keep it emissions legal you should try Hooker comps 2460's with air-tubes (1-5/8's primaries 3" collector) and if not just order them without the tubes ...They are a heavier gauge and only $130 out of jegs, plus u won't have any problems installing them like clearence for the steering shaft......then send em to JetHot and have them coated inside and out with there sterling silver ($200).....that's only $330 for headers...I don't know if ur on a budget but budgetting everything sometimes helps in the long run for other mods.....the headers also come with o2 bung on headers the only thing u have to do is drill it out......also u should think about bending your own pipes or maybe even having an experienced muffler shop to do it for u... I know my exhaust is almost $800 without labor that's just for parts....anyways look at some of the dual exhausts down the trans tunnel.... I opted to use some Summit Stainless Steel Long Tube Chambereds (69-Camaro SS muffs)..(for a deep sound... or u could order there shorter ones for a louder sound, a lil more money) down the trans tunnel and I have a side exit before the wheels...u can get them in 2-1/2 to 3" diameter... if using a big engine (400sb) although the smaller headers may seem like a bad idea it will opt for more horse and maybe a lil less torque while 1-3/4 primaries will opt for more torque and a lil less horse it's kinda like a crap shoot... anyhow since your car is lower and it would be easiest to go down the trans tunnel u could still use 3" tubing....this would be the most professional way to do and u could also have the exhaust exit whereever u want....this setup is a deep nostalic kinda sound... but with a larger motor it sounds kick ***...this setup prolly runs around $600-$700 with everthing included....muff/cats/tips/and piping. if you have even more money u could do all stainless steel piping which would run maybe 200 more...