i have an 85 305 iroc-z and i just got it and i am planning on putting on a new exhaust system very soon and i was wondering what kind of setup you guys would suggest going with for that car right now it is stock but once i save up a little more money i am planning on putting on a dual system with high flow cats and glasspacks, would this be a good setup for my car i am planning on keeping the stock headers for awhile and doing a lot more mods. I plan on having a lot more power than the engine is putting out now. thanks

 

I good catback is always a good place to start but you said you wanted to go duals, best bet is to save up enough and go with full headers and do your dual GP and HF CAT's all at once you will notice HUGE power gains, from that alone, then once your car can breath out the A$$ end you can work on anything on the intake end and it will be better received and your money will be better spent.

Just my .000002 cents (bloody exchange)

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1989 Trans Am GTA, 5.7L TPI, TH700-R4, T-Tops, dual cats, 9-bolt rear, 3.27, Dynomax muffler, K&N
1992 Camaro RS, 5.0L TBI, T-5, T-Tops, L69 Dual Snorkel, K&N - Sold

 

I've got an 85 and I'm putting on coated hooker super comp shorty headers, random tech high flow cat and a hooker catback, should have it on in a couple of weeks will post clips

 

Everything sounds good except the glass packs, I mean, they are alright but, If I could help it I would try and stay away from them.

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I Love Smokin Tires
(stangs fear me)

 

why do you say stay away from the glasspacks

 

Glasspacks rob flow , and I haven't heared a f body that sounded good with them on look, into flowmaster or hooker mufflers, might do ya better (my opinion though) good luck

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I Love Smokin Tires
(stangs fear me)

 

For a 305, duals are unnecessary. At most, put on dual cats. But, a single 3" will be fine for all but the most high reving 305.

Absolutely stay away from glass packs. They are terrible for flow, only good for noise. Fellow out here has a '68 327 Camaro 4-speed he races at Bandimere, picked up .5 sec in the quarter by throwing away his loud, restrictive glass packs and putting on a pair of JC Whitney turbo mufflers I gave him. He's since rebuilt the engine with a better cam and picked up another .5 sec, the glass packs would have kept him from any improvement.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4. 2.93 limited slip. Cat-back from '91 GTA, ZZ3 intake, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/'87 LB9 block, ZZ3 cam, ported World 305 heads, Hooker headers & y-pipe, 3" Catco cat & 3" cat-back, Spohn SFCs).
57 Bel Air, my 1st car. '66 396, 9.7 CR forged TRWs, Weiand Action+, Edelbrock 1901 Q-Jet (Holley 3310 on the way), GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 600 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

 

wow i always thought glasspacks were just straight through tubes how can they have bad flow

 

A 2-1/2" inlet glass pack will typically have a 1-3/4" or 1-7/8" inner tube. Also, the outlet is typically smaller than the inlet. You can avoid the inlet/outlet differences, but that internal tube will still be the restriction.

The only thing they will increase is noise.

 

Huh i always thought Packs flowed well too, oh well not like i was ever gonna put them on my car. I think the sound is ok at best, depends on brand, but its more of a thing for old musclecars or 4X4s i think. Just my .02. I really like the sound of my flowmaster at idle, I've never heard the "drive by" sound of it though cause well, I'm always driving my car. It sounds GREAT revving down though when you lock it in gear and use compression breaking to slow the car down.

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88 Camaro (The mighty LO3 SC!)
305TBI/700R4/2.73/123,XXX miles
14" Open Element and Flowmaster 80 seires

Next up: headers and gears

 

well i think i'm going to go with some hooker compertition headers and a high flow converter but i'm not sure what type of muffler to go with i guess i will try out the glasspacks cause they are really cheap anyway if i'm not happy with those i will probably go with a flowmaster catback thanks a lot for all your help guys i'll let you guys know what i think of the system when i order it and get it installed.