ok heres the deal i bought slp 1 3/4 headers they will not fit, i am about to buy the super comp long tube headers. the only guy i could find to do a custom exhaust said i should go with 2" primarys to dual 3.5 pipes. but he also said it is near impossible to fit dual 3" out the back of the car. thus he said 3.5" side pipes. i am banging my head against the wall...and its starting to hurt. the guy also said 700hp 1 3/4 will be as useless as me putting dual 2.5" pipes any ideas before i go take an axe to my car. also , if i go with the hooker super comps, are they 3.5 or 3 primaries?

http://people.ne.mediaone.net/gdm/

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87 z28 bowtie aluminum 420small block dry sump crower lt. wt. knife edged crank oliver lt wt rods brodix track 1's super ram intake slp 1 3/4 headers accel dfi art carr 700 r4 3.42 gears ssm sub frame/ladder bars.....other parts on the way ,soon to be finished!! couple more weeks!!!

 

Shane B. Has some Hooker shorties and they are 3" outlet but the primaries are 1-5/8"

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

To be installed eventually far far far into the future: Yours if the price is right and I don't have to ship :
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

Header choice is all based on air flow and velocity. They are related and now here is an attempt to explain how.
Small tube headers keep the air velocity up at low RPM. Having high air velocity is crucial to proper cylinder evacuation. You want to create a low pressure area inside the header and you do this by having high air velocity going out.
Small tube headers become a problem at upper rpm's because there is not enough volume and you run into a crowded condition in the primary tubes.
Large tube headers do not function well at the lower RPMs because the air is falling out of the cylinder not getting sucked out.
Anyway that was a long rambling response which you probably already know but I was bored.
The 2 in Primaries are really big. I would hazard a guess that if you have a 350 the engine will not like to run untill about 3500 and you are not going to shift untill 7000. If you are only racing this beast then go ahead and do it and my God have mercy on your soul.

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84 Z28 383
Stripped w/Cage back halved w/ladder bars and coil overs and 9 inch
700R-4 3.73
I would have a time by now if I could ever get my car back from the shop!!

 

Do the brodix heads have the dual flange pattern?
If not there is no point going with any thing bigger the 1 7/8"
Have you dynoed the engine?
If it really make 700hp then yes 2" primary and 3 1/2" collectors are right, just as the guy said, who was he anyway, who's he work for?
I dont know if the Hooker SC make a 2" that will fit a 3rdgen.
Good luck

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91 B4C 305 TPI - SOON TO BE 383
TREMEC 5-SP, STOCK 1-BOLT REAREAND w/342 GEARS, K&N, AIRFOIL
EDELBROCK HEADERS, DUAL CAT TO HOMEMADE Y-PIPE & 3.5" SINGLE PIPE W/ FLOWMASTER, CRANK PULLEY, MSD, FUEL PRESS REG, COWL HOOD, WELD WHEELS
14.1@ 98MPH
-------------
OTHER RIDE
67 CAMARO - STREET CAR, BIG BLOCK, PUMP GAS
350TH w/ATI 10", 12-BOLT w/373 GEARS
10.47@129 1.55 60FT. ON MOTOR - ET-STREETs w/MUFFLERS

 

hey 91
no i have not started the car yet. but lingenfelter make allmost the same motor 420sb that produces 650hp (pretty sure) and that is with a smaller port, smaller injectors , slightly smaller cam ,and wet sump.
my car 420 dry sup ,.550 /.575 cam 244/255 @ .050. 215 cc brodix heads, ported super ram setup, 1000 cfm tb ,35# injectors, accel dfi (properly tuned i am assuming ballpark of 700hp. that is pretty conservative based on lingenfelters build spec). lpe spec was 615 bhp ...just checked!

but anyway i gave up and ordered hooker sc's. i think i am going to have to make my own custom 3" exhaust for it. because nobody in my area i have talked to so far wants to attpempt it. whats a few hp for a street car anyway street......muahhahaaa did i say that? so 1 3/4 will be fine i guess.

one more question should i do dual 2.5" or should i try for dual 3" the guy i talked to (which by the way is just a local guy who reccommedned 2" primaries, never said they made em for 3rd gens) said he does 2.5 and quite frequently..
i would like to keep stock type appearance as you cannot tell my car is anything but stock, until its running as burping and lopey and loud as hell. but as appearance goes and not sound i would like to keep it as stock looking as possible so i really dont want exhaust hanging down near the ground, but another fork stuck into the works...my ladder bar cross member spanning from one sub frame connector to the other limits the room i have too =( ohh how i wish i could dump out the hood or behind the fender without trouble with the cops

hehehehee i laugh every time i think about pulling up next to some shmuck in a stang..or on a motorcycle and blow the pants right off them. :0

i am going to shoot for about a 10.50 (not nhra legal) but a 10.50 non the less

lokkie at my works in progress
http://people.ne.mediaone.net/gdm/

and thanks for responses!

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87 z28 bowtie aluminum 420small block dry sump crower lt. wt. knife edged crank oliver lt wt rods brodix track 1's super ram intake slp 1 3/4 headers accel dfi art carr 700 r4 3.42 gears ssm sub frame/ladder bars.....other parts on the way ,soon to be finished!! couple more weeks!!!

[This message has been edited by 87tpi420 (edited August 16, 2001).]

 

yea, if your going for 10.50s you'll need those 3" pipes or a single 4"

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91 B4C 305 TPI - SOON TO BE 383
TREMEC 5-SP, STOCK 1-BOLT REAREAND w/342 GEARS, K&N, AIRFOIL
EDELBROCK HEADERS, DUAL CAT TO HOMEMADE Y-PIPE & 3.5" SINGLE PIPE W/ FLOWMASTER, CRANK PULLEY, MSD, FUEL PRESS REG, COWL HOOD, WELD WHEELS
14.1@ 98MPH
-------------
OTHER RIDE
67 CAMARO - STREET CAR, BIG BLOCK, PUMP GAS
350TH w/ATI 10", 12-BOLT w/373 GEARS
10.47@129 1.55 60FT. ON MOTOR - ET-STREETs w/MUFFLERS

 

you may want to try a step-up primary design. If you're planning on spending a good deal more cash(and it sounds like you are. You could use 1 3/4" to start, go 1 7/8", then 2" into a 3.5" collector. and make a custom 4x2.75" dual oval exhaust. I saw the same thing done to a 77 vette, the guy didn't want true sidepipes. Anyway, you could do that, put a race muffler in each pipe for the necessary back pressure, and have the pipes exit just in front of the rear wheels, so you can retain your rear suspension. It'll be pricy, but I've seen it done.

Anthony

p.s the stepped headers will widen your powerband as well. it may shave a little off the top end, but it is very effective at smoothing out the powerband.

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previous ride: 87 Camaro LT
350, A4.Comp Cams 268H, Edelbrock Preformer intake, Hedman Headers and y-pipe, gutted cat, No AIR/smog pump. 14x3" Open element K&N, Q-jet w/ D hanger and DA rods, adjusted AV spring tension and quick can.

Current ride: 1992 Camaro RS, K&N, Flowmaster, 305, T5, Black, T-tops, 76k miles.

 

How about a 3" to 4" Mufflex y-pipe and a 4" catback w/o the cat!!

Check out:
http://www.mufflex-performance.com//...ducts\new.html

http://www.geocities.com/cfrios/Phil...l?996948051310

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Phil87IROC
Blue '87 IROC, 383 Crate Motor, KB pistons, AFR 190 heads, TPIS ZZ-9 cam, Edelbrock RPM intake, 1" TD spacer, Hooker SC/LT headers w/ Mufflex Y-pipe, Edelbrock 750 cfm Carb (#1411), Stock T-5, GM 3.42 gears w/Auburn posi.
Ohio Valley Dragstrip (KY) Trophy Bracket WINNER - 8.39 ET on a 1.82 sec. - 60'. Best MPH = 84.44. Still Tuning Carb!
Red '89 IROC L98, TES w/Flowmaster, 1LE DS, 700R4, T-Tops, K&Ns w/open air boxes, 160 T-stat, Hypertech Chip, gutted MAF & CAT, Jacobs Ign., 53kv coil, MSD wires.

[This message has been edited by Phil87IROC (edited August 18, 2001).]

[This message has been edited by Phil87IROC (edited August 18, 2001).]

 

Are you selling those SLP headers?

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89 IROC-Z 355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# svo injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), 3" Random Tech cat, Mufflex 4" cat back, B&M shift Kit, 2500 converter, 3.27s, and 4-wheel disc. Chip is custom(doing it myself). 2 1/2 Harwood and just painted.

 

yes i am. the slp's. i am going to pop the dimples out soon. email me at gdm@mediaone.net

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87 z28 bowtie aluminum 420small block dry sump crower lt. wt. knife edged crank oliver lt wt rods brodix track 1's super ram intake slp 1 3/4 headers accel dfi art carr 700 r4 3.42 gears ssm sub frame/ladder bars.....other parts on the way ,soon to be finished!! couple more weeks!!!

http://people.ne.mediaone.net/gdm