Header and manifold Thread

[TheOtherNick]

nope they dont work.

[dpzelenak]

thats what i thought, do you know of anybody that sells one for the 3.1 or 3.4, ive looked but havent found anything

[TheOtherNick]

Milzy Motorsports - American Muscle, Reborn

[dpzelenak]

wow im an idiot, ive been on that site hundreds on times and even be in contact with someone from there, never even thought to look under the exhaust section,,
thanks

[blueguy]

They don't make headers for the 3100 or 3400...just the 3.4 DOHC from the pre-gen. They have really good stuff...as in...you could do a 3500 top swap with a heads/cam and probably gain about 50 crank horse or so. It would run pretty decent for an N/A car. They do sell ported manifolds for it though...I'd just get a dremel and take off my factory ones and port them out for free...and buy a downpipe from them instead.

[dpzelenak]

i know they make ported 3.1 intakes, maybe 3.4
but i plan on takeing a 3.4 and top swaping with a 3.5

[Xanthous]

Speed daddies are 1.75" primaries.

how come their site says 1.5"?

HEADER - STAINLESS STEEL - 97-03 PONTIAC GRAND PRIX 3.8L V6

[matt5112]

Pontiac Performance Racing Products for International Sales from SSAutochrome Inc.

someone measure them?

[DanGTP]

O.D. of the Speed Daddy headers measured 1.669" That would put it at something close to 1.5" I.D. primaries.

Now, someone with real SSAC's go measure one of your primaries and we'll compare results.

Personally, I believe 1.5" is large enough for 95% of the GP's using headers.

[TheOtherNick]

I will measure my primaries tomorrow on the SSAC i am pretty sure they are 1.75

[matt5112]

one and fiveeee eighths?

And i agree on the primary size.

My boost levels went down going from pacesetters to SD's.

[Xanthous]

You get a measurement nick?

[TheOtherNick]

Its tomorrow allready? I will be sure and check today

[Derek81]

SSACs are listed as 1.75 in primaries on their site and are also listed as MILD steel.

[comengetit]

Alright ive ben debating getting headers for my gtp for a while now. its an 01 with 145000 miles, and the motor is a fresh 99 with about 45000 miles on it. i finally have the loot to get what i need. im still in debate mode tho. i dont plan on modding my gtp much due to the fact is my only car n i have to keep it reliable. i have read many threads n ive come to this conclusion with a few questions. i have no mods btw. i beleive this is what i need..... speed daddy headers, a high flow cat(probly universal), felpro manafold/header gaskets, various band style clamps and a shyt ton of copper rtv. now my questions are.... what moddifications will i have to do to get the high flow cat installed correctly with the headers n resinator.? do i need to rap these headers with anything to combat heat problems or will they be fine bare? Is there ANYTHING im missing? i have read the thread on sd install but any other tips or tricks to ease the install would be greatly appreciated. i plan on doing this myself and i hate workn on cars....so the less aggravated i can be the better(as always). thanx guys i realy appricate the feedback n helpful info this site produces. hopfully i can get the mindset to do these headers cuz i know its n important mod no matter your intentions.

Headers: REGAL/GRAND PRIX GTP 3.8 SUPERCHARGER STAINLESS HEADER | eBay

Cat: Thunderbolt High Flow universal Catalytic Converter 3" | eBay

[fubar569]

Do not wrap the headers on an all season car.

Headers look good.

the clamps required are:
(2) 2.25" stepped band clamps for the crossover pipe
(2 or 3) 3" stepped band clamps depending on your configuration.

Reuse your stock MLS exhaust gaskets. no need for felpros.

You can install the headers from the bottom by dropping the rear of the cradle about 2 or 3"...I find installing them from underneath is easier but i have a C body and didn't even need to drop the cradle. it went in with no effort. W body may be different. Go with what works best for you.

As far as mods for the cat? none required. you may have to cut/modify things a bit to make sure everything under the car is the correct length to bolt up to the stock catback. If there isn't a rear O2 bung you'll need one welded in. You WILL need to either make an O2 harness extension for the front or buy one from one of the many vendors online. You MAY also need to clearance the firewall for the front O2 sensor as on some cars it can contact it.

Apply the copper RTV Liberally. Even the EGR sealed perfectly with a little bit of it. it'll be your best friend here.

[comengetit]

thanx for the info. how would i go about clearancing the firewall if need be? and i need a new resonator to. should i buy a thrush glass pack and find a way to hook it all together or just buy a replacment with the flange already on it? idk if the flange is gonna come apart to easily.

[blueguy]

Bolt it up to the factory catback and the crappy resonator and drive it to your local exhaust shop and have them cut out the stock res...and yes, install a long glasspack...probably a 26"+ would be best.

Or...just drive it to your local exhaust shop with an open downpipe and have him fab up something...that's always fun.

[comengetit]

haha nice. i changed out the resonator last night for a thrush 31" oal glasspack. everything was good til i started the car n noticed a leak on my last slip joint(had to extend alil, needded 35" span). advance auto douche bag said i didnt need the rtv....so i beleived him n screwed myself lol. it didnt realy change the tone with stock mufflers but its red n will look good on my red gtp...for about a month lol. my frontend has drag and humms alil. i beleive its my wheel bearings so i may have to put the headers on hold once again

[GrandPrixGTP1]

Getting speed daddys seems like a lot of work.
If i got them a shop would probably charge me a good amount to install em..
makes me not want to get them.

I wouldnt be installing them myself.