Stepping down to a 1 5/8 primary kills the power factor for me, i was a 1 3/4 or better. Not that others might say there is no difference, i have a set of hooker supercomps i might be able to buy back from a friend i thought about using.


That is why i am asking input, but if you think that a 1 3/4 stepped to a 1 7/8 to a 3 inch collector wont do better than a stock manifold, you might be batshit crazy, LOL.

As far as spendage goes, i would probably be keeping them, this would be a permanent option for myself, a step to the 1 7/8 ad the 3 inch collector would seal the deal, i am sure a set of full length 1 3/4 wouldnt make that much power difference and it is a street car that will see the strip, not a dedicated track ride.

 

not looking for all out ET, youll be fine with what you want to do. the but-o-meter will not be able to tell the difference.
i cant stand leaving power on the table. it drives me bonkers.
street or strip.

 

I think you missed the first part of the thread. We love the Hawk's headers, BUT they do not fit cars using an auto trans. So us auto guys are left with either shorty headers, or fabricating our own long tubes.

I personally went with short edelbrock headers that are a direct replacement for manifolds. They are cheap, stainless, coated, and perform better SOTP wise, not to mention they look better than the ugly stock log type manifolds I had on it.

If some one can find a bolt in longtube set for a LSx swap that will also work with an auto - I'd certainly make those a 1st choice option.

 

what auto trans won't they clear? 4L60e or 700r4 or th350/th400? I ask since I know several guys running the th350/400 with those headers. I don't recall the 700R4 being much bigger. The cheapest and best option on a budget is hooker super comps with a ls1 flange welded on with 2 tubes moved. Maybe I should start buying sets of them and performing this mod, I bet they'd sell like crazy.....hmmm.

 

No tellin, i am running a Y56, but i just refuse to spend 700$+ for some damn headers when if i can make a set work and have half the money invested and only be down 5-10 HP.

We will see....damn bills...

 

They won't fit on a 4L60E or 700R. The collector runs right into the trans cable area on the driver's side.

 

th350/400 ok, just dont expect to use the 02 bungs located in the header.
will work for powerglide, but you have to remove the bung from the drivers side header and weld the collector back up.
WILL NOT WORK! with a B&M shifter unless you heavily modify the cable bracket, and even then, you have to have a hurst gear selector for the trans.... which makes it fun adjusting so you have all the gears.
had a hurst shifter in the car, everything a-ok fitment wise.
prolly burn through a cable with these headers and a glide.
they are quality built, respectfully.

 

not arguing, just stating facts.
unless you 100% do all the work yourself, 700 bucks isnt an outrageous price compared to todays market. the headers are all stainless, tig welded, very nice constuction.

id rather spend the money for the 5-10hp.

 

Well, as i am limited on funds, it is not going to happen if i want my car running this year.

 

it was tight, but the headers slid right in:

 

That is NOT a bolt in affair, your trans bracket is also modified to allow the pipe to pass right along side the transmission. That would require me to remove the bracket and modify it again, or buy the special bracket from BMR. Also, what are you doing for O2s? I remember hearing that the ports on the headers cannot be used due to space issues (certainly looks tight in that picture). That bracket/cable on the trans is also just as close as I have seen on another car that used the hawk's headers. Too close for me.

So do the headers "slide right in" yes. But can you hook them up without hacking up the trans crossmember or coming dangerously close to trans components/pan or having the O2 sensors 3-4 feet down stream?

Forgive me for skepticism, but I have seen very few people successfully use them on a 4L60E car without needing to modify either the headers or the trans crossmember. They are not "bolt in" like they are for T56 cars.

One more question, how did you route the pipe from the driver's side back over to the passenger side to hook it up to the dual catalytic converters? It seems too close to the pan/DS area to get it over there for stock routing. (which yes I require due to being a daily driver 1989, and needing to pass emissions tests.)

 

you can put the bungs for 02's in the y pipe, which is not 3-4 ft. i had mine about 6" past the collector. i dont see an issue with them being just outside the collector. im sure some disagree.

 

my oxygen sensors are in the bungs that are on the headers straight from stainless works. i touched NOTHING on the headers themselves to make them work. i even had a big bulky billet servo cover on the trans when i put it together and had no clearance issues.

the shifter linkage was modded a very small amount, basically hit it with the angle grinder. that part was too easy. if you can't handle that much, you should really reconsider an lsx swap in the first place.

the crossmember was modded because i desired more ground clearance with my dual 3" pipes. had i gone with a 2.5" pipe, i could have probably gotten away without touching that crossmember.

i have no cats, as the car is not driven in an area that has any kind of inspection...so why would i put them on?

 

That was my original point:
Routing with cats is near impossible, required in my area (without compromising ground clearance)
Requires remodding or buying a new crossmember
Requires modding shifter cable
Having an auto exacerbates the problem

For you it may have been "bolt on", but for some one with emissions concerns it will not be. Going back under the knife to modify the crossmember and shifter cable just for LTs is also not appealing. Hawk's won't even sell a Y pipe for the 3" headers, and why go 2.5" with LTs? If the headers were 300-400 I might sacrafice a bit to make them work.

Again, until some one comes up with a better fitting LT, IMO Hawk's aren't worth $800 bucks for shiny material. I'd rather leave a bit on the table and modify a used set of Heddman LTs for $80 bucks.

I never intended to bash hawk's for the product, but they don't fit well enough for me to justify the money, can you MAKE them work? Sure.

 

I thought longtubes weren't emissions legal at all because you have to move the cats right?

 

I had longtubes and passed emissions, they were hedman, just had to route it like stock or find a way to fit both cats under the floorboard on each side. I used the stock routing on the passenger side. Currently with the true duals I do the same thing. I know they will fail you if they are picky about location, but most of my concern is just being able to route it with cats on there to pass the sniffer.

 

tons of room to put round style cats under there.
pass side is wide open and could be put in strait. the drivers side would have to be put in at a 45 degree angle after the crossmember.
you can make the y pipe longer and the catback shorter.
im not telling you to do anything you dont want to do, but you post like it cant happen.
nothing is ever bolt on, IMO.
even when it is, i still mod it!

 

nobody said those headers were emissions legal. the guys in california have zero options then because no swap header has cali smog certs.

a modded set of hedman longtubes is a LOT more work than modding a crossmember and grinding on a shifter cable linkage, and you STILL can't package cats. and since they're home made, good luck getting anyone to pass those. your argument seems to be lacking any concrete reason why you wouldnt' want to use them...other than maybe the price tag. but again, if that's a concern, you may want to reconsider this swap, as it's an expensive swap by nature.

if you go to the trouble of making your own headers, i'd like to see some awesome stepped 1 3/4" - 1 7/8" or larger step headers that will really allow that 6.0l of yours to see it's full potential.

 

I don't think I would have any reason to go that large, if I ever step up to LT and have the cash, I might try the 2.5" Hawk's (but yes, as the OP says the price is prohibitively expensive atm), or mod an old set of hedman LTs if they pop up for cheap. I doubt that unless my motor is making north of 550rwhp i'll leave much on the table with those. There are people running 9's on shorties, I know mine isn't that fast lol

 

Yea, my buddy had shortys on his IROC with a 408. Thats why i am thinking about doing the 1 7/8 patriots and chop them at the primaries and run the 1 3/4 into the larger pipe. i think a stepped shorty will make plenty of power and not leave much on the table really.

 

who is running 9's on shorties?(that isnt boosted)
i dont know of anyone.
youd be suprised how large of a header these motors like.
stock 346 will pick up with a std 1 7/8.
i just put a set of 1 7/8 on my 408, but havent had the time to get my exhaust mated up to the new headers. i found a set and bought them.
i was going to do 1 7/8 to 2" if i had to have them built.

 

9's on shorties? n/a or n2o? i think not....maybe in the 1/8.

you seem to be a bit uneducated about the way these motors work...they like big headers as stage20 pointed out.

 

are you refering to an LSX motor when you say 9's on shorties? a BBC maybe, but I just don't see that on a smallblock be it LSX LTX or even a GEN I.

 

Yes, 9s on shorties but with lots of nitrous.

 

On an LSX, LTX, Gen I or BBC?

 

This whole topic is supposed to be on a LS platform, so yes, a LS engine where i stated 408.

 

 

Like i said though, lots of nitrous, 2 kits.

 

so what you are telling me is the shorties have nothing to do with him running 9's.
lots of nitrous.... 2 kits.... i could run 9's on stock manifolds.
why does it take "lots of nitrous" and "2 kits" for a 408 to run 9's?
even in a heavy car at altitude, a decent 408 should be able to get in the mid 10's on motor, i would hope.

we are comparing apples to oranges here.
longtubes all the way.

 

I still have a set for sale. $650 plus shipping is the best I can do. I already have the turbo headers and need to get these sold. Thanks, Mike.

 

Hehe, you were thinking of the same car zone :-P

Yes he ran it with nitrous, but I think the point was that they aren't so severely choked on shorties that they will crumble under a big motor. 9.92 is a pretty good number for a full weight firehawk with shorties and a single 3" exhaust using the stock 2otl setup that he has that motor in now. I believe he said it makes 715rwhp, I am certainly not making anywhere near that.

Here is the new car: http://www.youtube.com/watch?v=bTEid...eature=related

 

9.92 on 2 kits?
whats it run on motor?
im not saying the exhaust is hurting his performance.
weight, gear, stall, etc can all be factors.
just cause he has a 408 means diddly. he may have a stock set of 241 heads and a stock cam in it for all i know.

if it puts down 715, he is in serious trouble with his ET's.
i only put down 510, and run 6.20's, which could go 9.80's in the 1/4. im a max effort setup, but im getting it done all motor.
friend david only makes 675 to the tire and he is running 5.70's on motor.... thats 9.0's 1/4 mile, all motor.

id like more info on the car.

 

1986 IroczEngine408 LS1 w/ 2 stageTransmissionTurbo 350Axle/Gears3:73,3850 lbs , best of 9.92 @ 138They just dope everything out really. They are not known for making good numbers on motor man. The car is a roller right now, last i checked anyway.Car is over 4150 with the driver, would have liked to see what it would have done with deeper gears.

 

No one is saying shortys are better, it is just an alternate option and if possible i am trying to see what i can do to make as much power as possible without shelling the 800$.

 

4150? they have a wall of subs and amps in the back of the car? no wonder they need nitrous.
what do you mean by they are not known for making good power?

 

Yea, the car was fully loaded, leather, cage, sound system and the works, if you know the guys that built that one, they are N2O guys, they put tons of dope on everything and dont make great numbers on N/A.

 

Yeah, if I remember correctly the whole motor was set up specifically for nitrous, and apparently loves it. The motor has been through what, 2-3 cars and NOS systems, etc. etc. But yes his N/A number wasn't impressive(i'll keep it secret) lol, with nitrous it was either 715CHP or 715rwhp.

@zone
That was one of my initial points, sure we will be leaving power on the table with shorties, but obviously they are sufficient enough for some of us, and personally I like the ground clearance and ease of removal. They only cost me 200, they are stainless, coated, and flow nicely (compared to the log style manifolds I had).

IMO, I would spend the money on the cat back, a 3.5-4" mufflex would be NICE, and then just have some one make you a good Y pipe to hook it up and call it a day. There are plenty of people who either don't have the money, or aren't blessed with emissions exemptions - they get by just fine on shorties.

If I canget out to SAR this friday I'll let yall know what it runs, It's been a long debugging task getting it all running right. Dyno'd 289rwhp with log manifolds, single 2.25-2.5" exhaust, busted driver's side flange (lean O2), and a dead pass. side O2. It was also only reading 3.8v max tps at WOT lol

 

how would you route said y-pipe? the f-body oil pan leaves so little space between the pan and the k-member that there is no way you could put a factory style y-pipe on the car. the pipes would HAVE to go under the transmission crossmember. the only other option would be to run a tubular k-member...and with that much money tied up into a k-member, you might as well run the Hawk's Longtubes...

 

I have it routed similar to stock right now, with shorties and cats. My advice would be to have a better shop do it, mine needs to be redone with some prettier bends, but it works.
Pipes are both wrapped in heat shielding now, I didn't like how close to the pan the driver's side pipe was.


I went with this to pass emissions (going from single 2.5 to true duals with cats)

 

i'm very lucky then. (a) i can build my own stuff as i can fabricate. (b) i don't have to worry about emissions.

with being able to fabricate, i can build as many exhaust systems as i feel like because the overall cost of the stuff is so much lower. my dual system is the third system i've had on the car since i put an lsx in the car.

yours doesn't look bad...i probably could have come up with something like that if i was running a shorty. i'm racing mine though, and i'm looking for ever last ounce.

 

So true, i am so glad to have my own damn welder, i just buy mandrel bends and go to town as i see fit.

 

No kidding, I'm about to invest in a decent mig to do it myself. Tired of shops not quite understanding what I want, or saying it can't be done. I think for the next setup i'm going to get a mufflex 4" back, then make my own Y pipe and call it done. The duals are nice, but on this particular cammed car, they sound like crap at idle.

 

Crap at idle? Just depends on the mufflers, every one sounds better and worse.

 

It just sounds kinda of muddy, maybe a X/H pipe would help? I think it's just because of the cam, but I'd like it to sound more "crisp"
http://www.youtube.com/user/elementa.../1/hyRWfFqCQaE

 

That is the mufflers man, not the engine itself, try it with straight pipe and it will sound WAY different.

 

i'm sure an x-pipe would increase the crispness. but so would going to a better flowing muffler. i sell those things at work...terrible...

 

Well, i think i will be bale to make this work pretty easily and what not, it will be my first attempt to do such a thing, i am sure it will be pretty easy, i am selling some parts to get my project rolling again and i hope to have income tax left over to help get the headers to finish: