danziger

Yes, I've done a search...
I have a cherry 1991 Formula 350 (completely stock) and want to add a few HP. My requirements are pretty specific and I would appreciate any help...

• Able to be installed with good hand tools on ramps/jackstands- I'm a decent mechanic and have done headers on LS1 F-bodys and 5.0 Stangs, but I don't have a torch or compressor (yet).
  
• Quality- I'm willing to pay a little extra for a better header, or one that installs with less headaches.
  
• Cats- We have visual inspection here, so shorties to the factory Y, or a catted Y is needed.
  
• AIR tubes?- Obviously would prefer to remove them, but will they throw a code?
  
• Vendor- Board supporters would be great, but if you have a part # with Summit or Jegs at a great price...

Thanks in advance!
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I forgot to add that absolute HP isn't the goal. From what I've read 1 5/8" primaries should be adequate for a bolt-on L98, correct?

b4c-1le

The Edelbrock headers are designed well and very easy to install.... you will likely have to cut/weld your factory converter pipe to adapt them. I had the dual cat one which required this but not sure about the single cat - it may be a true bolt on. This is the best bang for the buck. I think you can pick them up for under $400 at Summit or Jegs. Very well engineered. I put a set on my '87 15 years ago and they are solid as ever. They used to come coated from Edelbrock, but I'm not sure if they are doing this anymore. At one time you could order them with or with out air tubes. But it would be easy to cut them off and plug them up if you can't anymore.

If you are interested in "the best", I have a new/never been installed set of SLP headers with the dual cat y-pipe extensions.... You can't buy these anymore unless they're used. But I'm looking for some good $$$ for them as they are pretty rare at this point. Let me know if you are interested...

Rich

JamesC

iTrader: (5)

If you haven't looked at it, the sticky at the top of the page provides a ton of info. The board favorite seems to be the Hooker 2055's. The following system is direct fit:

Hooker 2055's (Jeg's 520-2055). Catco high-flow converter (Summit CTO-9118). Hooker catback (Summit HOK-16823HKR).

JamesC

danziger

Rich,
Thanks for the reply. I'm trying to avoid any cutting/welding as I may as well have them installed if that is necessary. Otherwise, the Edelbrocks look nice and I scoped them in a couple threads and in the vendors catalogs.
I'd definitely be interested in the SLPs if they fit the criteria. Drop me a PM or benjaminr@hotmail.com Ben
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James,
Yah, I read the sticky and a bunch of threads. There seems to be a lot of conflicting info, but I agree that the 2055s are popular. I'm not interested in the "my header is best" or "my header makes the most HP" tangents that a lot of the discussions seem to take.
Thanks for taking the time to link up a direct-fit system. I'll have to re-read on how the 2055 installations went.

danziger

Threads like this that seem to have conflicting info are why I wanted some fresh advice...
https://www.thirdgen.org/forums/exha...highlight=2055
Thanks in advance!

five7kid

iTrader: (14)

The factory cats have welded inlets, I believe. You're going to have to do some cutting and welding.

Your '91 should have dual cats. That is a major disadvantage to the Hookers. But, Hedman makes a dual cat set, so I'd recommend you look into them.

I'm not a particular fan of the way TES routes their primary pipes. But, they are a viable option.

Nobody mentioned Board member Dyno Don - haven't heard anything negative about his product. They aren't factory made, so you may not be able to call him up and get them shipped the same day. PM him if you want to know what he can do for you. A.I.R. delete is one thing he offers.

joeblue83

iTrader: (8)

I would second the dyno don header option. I had a set of the slp's and there y pipe is smaller than the stock one I had on there. Dyno dons have no clearance problems with the steering shaft and the y pipe is an honest 2.5 unlike the slp which they say is 2.5 but when you measure it, its 2.25.
Just trying to get you the best set of headers with the least amount of headaches

danziger

Are we talking hack-saw cutting, or wheel/grinder cutting? I'm not afraid of a little work, but the Formula is pretty clean and I don't want to butcher-job her. Thanks for everyone's advice!

five7kid

iTrader: (14)

It could be done with a hack saw, but a cut-off wheel or Sawsall would be a lot easier and quicker.

danziger

Looking like the Hookers or Dyno Don's are the way to go...

b4c-1le

Check these out.... pretty sweet deal!

http://cgi.ebay.com/ebaymotors/ws/eB...ksid=p3907.m32

joeblue83

iTrader: (8)

I thought they were the 1 3/4 tubes not the 1 5/8 that were rare. If they are the 1 5/8 there are plenty of companies that make this, but 900 dollars. I hope nobody buys these. You can almost buy two sets of dyno dons headers for the price

five7kid

iTrader: (14)

While I normally recommend the Hooker 2055HKR's, for a dual cat car you'd have to be willing to replace the entire exhaust, or at least get a single cat and adapt it to the cat-back. Doesn't sound like the original poster was willing to do extensive modifications.

If you don't do Dyno Don headers, I'd say go with the Hedman dual-cat set.

1-5/8" primaries were recommended by SLP for 305 cars. They recommended their 1-3/4" primaries for 350's. Not sure why that is, as most shorties are 1-5/8", but I'd assume they knew what they were doing.

Mikz86TA

iTrader: (4)

I didnt read every post so forgive me if this has been mentioned.
But whatever route you go, get some coated ones. Even if you have to send them to get coated yourself. If your car is as cherry as you say it is, then you will not be happy when you open your hood in a week and they look rusty.
Typically JetHot is the #1 brand of aftermarket coating. I think silver ceramic and black are the coating options as well as different heat levels. They are also done inside and out I beleive.
Alot of header companies use an aftermarket coating company anyways, and some do it in-house.
PMFL is another good coating brand. My freind just installed a new set of Kooks stepped LT headers on his GTO with PMFL coating. PMFL offers their coting in colors. He got Red and they look great. PMFL is located in Florida. Google them.

Also look at the headers specs. In any header, make sure the header flange (at the head) is thick. The biggest issue I had with my old Headmans was the bolts backing off a bit. Caused gasket blow out. The reason is the thin flange moves or expand/contracts during the heat and cooling cycles. Thinner metal will 'move' faster when heated and cooled. Result was a bit of warping in the section between the tubes and also the backing off of bolts.
The SLP's I got have induvidual flanges and they are very thick. Also the Gibsons on my truck are thick. Either have given me any issues and are both on the original gaskets.

Tube gague. Again, go with whats reasonably thicker tubing. The better it will be at not expanding and contracting with the heat/cool cycles.

Tube diameter. Most recommend a 1 3/4 primary on a 350 and up engine size. If its a 305, then the 1 5/8 is suffecient.

Hope this helps

Timothayyy

iTrader: (2)

Could get Hooker 2460s, I have those and like them. I saw someone in the classifieds selling them a week ago or so maybe, should check it out.

If I went back and did my exhaust again, or got another thirdgen id get the dyno don headers though.

blacksunshine'91

iTrader: (10)

Regarding the cats; I recommend going with Random Technology cats. I have two of them on my car. A few years ago Car Craft did an article on the flow rates and effectiveness of the cats. The RT ones were the best on both accounts. On their 500hp motor, the cats robbed a whopping 3% hp! Many of the high flowing cats flowed better than the stock cats, but did not come close to being as effective in cleaning the air. I got the Random Tech cats from Thunder Racing. Not sure if they still have them or not anymore.

Dyno Don

iTrader: (7)

RT cats are way over priced and no better.
In fact, poor construction.

Timothayyy

iTrader: (2)

Ive got a cat-co, its cheap and ive had no issues with it at all.

Stephen

iTrader: (12)

You mentioned cutting off the AIR tubes....

If you do, the car will no longer be street legal, despite no emissions testing, if that is the case in your area. AIR tubes are a Federal requirement, regardless of your county or state laws.

Just an FYI.

danziger

Hmmm. I had figured 1 5/8s primaries would be fine on a bolt-on L98. I have no problem with leaving the AIR tubes/pump on the engine. I will pay extra for quality and ease of installation. Just wanted to clarify...thanks for all the input.

b4c-1le

The SLP's are a good choice... keep in mind that these were the ONLY headers sold over the counter by your GM dealer, and were the only header that could be installed and not void the factory warranty. This was the beginning of SLP's relationship with GM which led to the Firehawk and SS programs... As quoted from SLP's sales brochure "these are guaranteed to produce more torque and horsepower than any othe header currently available..." and they fit right and maintain all emisions even in California.

danziger

Sounds good, but they are currently discontinued, correct? I'd have to try and find a used set... Also, are 1 5/8 primaries a big restriction on a bolt-on car? Thanks to everybody taking the time to respond!

b4c-1le

New set available on e-bay right now....

danziger

Whew! $940 without cats. I'm watching them as an option, but jeez...long-tubes for my Z06 are not much more than that.

b4c-1le

yeah....but somebody bought it as they knew that they weren't gonna find it anywhere else.....it's called supply and demand my friend!

ringo234

I have Dyno Don's headers and Y-pipe and would have to say I would get them again. Get Dyno Don's, you won't be sorry.

TheScaryOne

iTrader: (3)

Dyno Don's. Whenever I put on headers, that's what I'll put on.

Shinobi'sZ

I have to agree... I have been searching for headers and after owning and modding two C5s (I sold my IROC Z in 1995) I have always used LT headers as the only choice. But recently I inherited a 1991 Formula 350 (all options..I think) with only 12K miles on it that had been garaged since 1992 and not driven....it still has brand new stock tires..but the rubber has gotten hard from sitting for 16 years.

Anyway after looking at the stock "log" manifold it became painfully obvious that it was a horrible piece to stick on a SBC.

I like LTs but they look like a pain in the azz and I'm not paying Corvette inflated prices or looking to do a lot of modification to other parts to install.....although I could change my mind, I'm just not interested in making this Bird (my Daily Driver) a 500bhp bolt on car like I did my 97 C5 or my 1000bhp (Z06). Stainless Works makes the LTs for Hawks and the Hookers look similiar but don't come with a Y pipe and are not stainless steel...but a lot cheaper....so they are definetly options to consider.

Dyno Don PM'd me his 1 3/4" shorty headers and dual cat/Y pipe setup and they look great. While I am not a big fan of shorties on an LSx as the LSx cars have pretty good manifolds from the factory when compared to "shorties" there is very little hp/tq gain vs. LT headers (LTs make a big difference). Anyway Dyno Don's headers seem to have everything needed to wake up a bolt on L98 even up to 500bhp. I am 99% sure I am going to pull the trigger and order them from him...just want to weigh out all of the options first...but it looks like Dyno Don's will be my header choice for the following reasons.

1 3/4" primaries
dual cat setup
fitment
price
quality workmanship
tested design over 500bhp

They do require welding to the cats...but I am not concerned about that as the benefits out weigh the simple welding that needs to occur.

TheScaryOne

iTrader: (3)

You could always weld a flange to your Y-Pipe, and then weld a flange to your cat. I dunno how the dual cat setup goes, but if you work out the fitment once, all you'd have to do is weld new flanges to new cats when you replace them.

danziger

I've PMed back and forth with Dyno Don and his headers look amazing. My military career keeps getting in the way of me pulling the trigger on his headers. I will keep you guys posted as soon as I can get home long enough to do any work on my Formula...