Glasspacks or flowmasters? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

gotmud · 01-16-2004, 11:45 AM

Glasspacks or flowmasters?
Any thoughts? Wanting to hook one or the other up to my stock cast iron manifolds. 68 lwb sbc307

Jace's68 · 01-16-2004, 11:50 AM

Flowmaster's (2 chamber)

**old Rusty C10** · 01-16-2004, 12:22 PM

ive never used glasspacks but i have flowmasters and never had any problem

70ChevyLongbed · 01-16-2004, 12:37 PM

I've got Flowmasters runnin' thru stock manifolds off my 307... I like 'em a lot!

CPNEJR · 01-16-2004, 12:54 PM

Flowmasters for sure

I've heard what they sound like on a 350 with headers so I would think they would sound somewhat the same

I know I like em' because I've sceemed up a plan to put on a set from that truck but I have to cut em' down to size

cause they were off a longbed and I got a short

IMO defidently FLOWMASTERS

Moloko · 01-16-2004, 01:01 PM

Neither; get dynomax ultraflows.

my69camaro1 · 01-16-2004, 01:32 PM

Flowmasters the only way to go, American Thunder 40's series.

Glass packs have the fake (Loud) power sound.

shuttermutt · 01-16-2004, 01:38 PM

Pick up a set of Flowtec Afterburners. Take the money you'll save and buy a beer for all those guys that will realize they could've had a truck that doesn't sound like everyone else's. If you couldn't tell, I like mine.

**JIMs70GMC** · 01-16-2004, 01:41 PM

I have summit "welded" mufflers which are chambered mufflers like the flowmasters and cheaper.

CliffB · 01-16-2004, 02:01 PM

My 72 C20 had glasspacks when I got it. I thought it sounded pretty good. Then I put on a new exhaust system with 2 chamber flowmasters (40 series). It sounds much better with the flowmasters than it did with the glasspacks.

One of the big differences in sound I have learned about is the size of megaphones if they are used. The exhaust shop explained this. We all know how a voice megaphone amplifies sound. I put on tips that are larger than the rear pipe when I put the flowmasters on the C20 truck. They work like voice megaphones and the sound waves are allowed to expand as they go from the tailpipe into the larger diameter magaphone tip before they leave the vehicle. Exhaust sound is louder than with same diameter exit tips.

My recent K20 has the same flowmaster 40s as the C20 but with smaller outlet tips. There is a difference in how they sound. The K20 is a little quiter than the C20, even with the same pipes and mufflers.

If you want louder, you can use tips that are a little or much larger than the tailpipe diameter and get more sound. Or just keep the tips the same size as the pipe and the sound will not amplify beyond what is governed by the muffler and pipe choices.

I'm not trying to be a scientist, or positive that what I observe is the only truth, but what the muffler guys told me agrees with what I hear and how I know voice megaphones work.

melloyello · 01-16-2004, 02:02 PM

i have glasspacks they are noisy but kinda nice if ya wanna bug the soccer mom in the minivan next to you as shes yackin on her cell phone and puttin on her make-up instead of paying attention to the road

gotmud · 01-16-2004, 02:39 PM

What size of inlet and outlet did the 68 Chevy 307 come with? I assume I want the inlet to go over the pipe and then c clamp it on.

shuttermutt · 01-16-2004, 02:54 PM

I believe the factory small blocks used 2-inch, didn't they?

CPNEJR · 01-16-2004, 03:06 PM

Yeah all the small-blocks are 2 in. stock size

cdowns · 01-16-2004, 03:38 PM

i bought bargin turbo mufflers at a local auto parts for about $20 each i've got better things to do with my money than to try and impress people with overpriced mufflers

kaycee · 01-16-2004, 03:46 PM

Yeah what cdowns said

lukecp · 01-16-2004, 03:54 PM

Defenitly flows!

I have had both and i like the Flows 10x better!

SWEET7T · 01-16-2004, 05:01 PM

Flowmasters!!!

Slammed67 · 01-16-2004, 06:54 PM

Neither. Dynomax.

MMGOODIE · 01-16-2004, 07:31 PM

Quote:

Originally posted by cdowns
i bought bargin turbo mufflers at a local auto parts for about $20 each i've got better things to do with my money than to try and impress people with overpriced mufflers

the true idea behind mufflers is not sound but performance. The interior or should i say "inferior" design of a cheapy is almost nothing compared to the interior design of say flowmaster or comparable. I am sure you gained nothing (HP wise) from your cheapies were someone who dropped $75.00 each on the flows gained probably 15% more horse.

I am not trying to sound like an a$$ but i went through this with my wife when it came to my 71' LB. sorry if i have come off that way.

as you can tell, i think the flows are best performance wise.

Martin64 · 01-16-2004, 07:36 PM

I have glass packs with 2 1/2" pipe and they are pretty loud. I like it but I'm not so sure how legal they are. One thing for sure is the soccer moms don't like 'em.

*rage'nrat638* · 01-16-2004, 08:29 PM

HOOKER AREO CHAMBERS
HOOKER AREO CHAMBERS
HOOKER AREO CHAMBERS

71swb4x4 · 01-16-2004, 08:35 PM

Flowmaster - had them on my last 2 trucks - great mufflers.

Shawn

ckenwright · 01-16-2004, 09:11 PM

Dynaflow will out flow anything you can find, FlowMasters have a reputation for the welds coming loose and choking the exhaust. Glass Packs do not flow very well at all and are probably the worst decision you could make.

*1972C10* · 01-16-2004, 09:16 PM

I just got two new flowmasters delivered for 91.98 here is the link where i got mine he has them in most inlet outlet configuration and sizes.

If this auction isnt the size and conifg your lookin for he has links for the other styles of two chamber flows

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2454453908

01-16-2004, 11:45 AM	#1
gotmud Registered User Join Date: Oct 2003 Location: Cumming, Ga Posts: 234	Glasspacks or flowmasters? Glasspacks or flowmasters? Any thoughts? Wanting to hook one or the other up to my stock cast iron manifolds. 68 lwb sbc307 __________________ Glenn Cumming, Ga (68 C/10 Fleetside LWB 307 (64 C/10 Fleetside Shorty Custom 350, with 73 donor parts aplenty) (2001 Porsche Boxster S - 168 MPH of fun) (2005 Chevy Avalanche Z71 1500)

01-16-2004, 12:22 PM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	ive never used glasspacks but i have flowmasters and never had any problem __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

01-16-2004, 12:37 PM	#4
70ChevyLongbed Howzit?!? Join Date: Jan 2003 Location: Maryville, TN Posts: 1,265	I've got Flowmasters runnin' thru stock manifolds off my 307... I like 'em a lot! __________________ Jason Hawaiian-J 70 Longbed, 307, Edelbrock Carb 1404, Edelbrock Intake 2101, Dual Roller Timing chain and gears, 214/214 cam, Comp Roller Rockers, dual Flowmasters. 1999 Chevy Tahoe 2004 Mini Cooper S 71 BMW 2002 - Sold

01-16-2004, 12:54 PM	#5
CPNEJR Registered User Join Date: Sep 2003 Location: Franconia,N.H. Posts: 1,029	Flowmasters for sure I've heard what they sound like on a 350 with headers so I would think they would sound somewhat the same I know I like em' because I've sceemed up a plan to put on a set from that truck but I have to cut em' down to size cause they were off a longbed and I got a short IMO defidently FLOWMASTERS __________________ (Only) Member of the CPNE Fan Club Aint that the truth 67 C-10 350 with 3-speed tranny and 308 gears swb step 82 Z28 Camaro 355 small block over 350 hp and a borg warner super t-10 (blown engine) 72 Chevy K20 Suburban (future project) 70 Chevy K20 now 68 GMC K2500 2003 Chevy 2500hd ccsb 4X4 (daily driver)

01-16-2004, 01:01 PM	#6
Moloko Hoarding Rusty Objects Join Date: Aug 2002 Location: Slatington, PA Posts: 267	Neither; get dynomax ultraflows. __________________ 1985 Chevrolet K20 Silverado 1994 GMC Yukon Follow me on Youtube! - http://www.youtube.com/user/FuelInjectionSucks

01-16-2004, 11:50 AM	#2
Jace's68 Registered User Join Date: Sep 2002 Location: Kentucky Posts: 107	Flowmaster's (2 chamber)

01-16-2004, 01:32 PM	#7
my69camaro1 Young One Join Date: Oct 2003 Location: La Porte Indiana Posts: 138	Flowmasters the only way to go, American Thunder 40's series. Glass packs have the fake (Loud) power sound. __________________ 69 R/S Camaro 79 K5 86 M1008 11 P71 Vic 12 Ram 3500 18 Ram 2500

01-16-2004, 01:38 PM	#8
shuttermutt Don't say "Oops!", Doctor Join Date: Nov 2003 Location: Houston, TX Posts: 677	Pick up a set of Flowtec Afterburners. Take the money you'll save and buy a beer for all those guys that will realize they could've had a truck that doesn't sound like everyone else's. If you couldn't tell, I like mine. __________________ 'Mutt 1968 CST LWB: R.I.P. 1967 Chevelle: TPI 454 beast 1967 C10 SWB: Claimed when Bumpster didn't put it on his list

01-16-2004, 01:41 PM	#9
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	I have summit "welded" mufflers which are chambered mufflers like the flowmasters and cheaper. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

01-16-2004, 02:01 PM	#10
CliffB Registered User Join Date: Dec 2003 Location: San Leandro, CA Posts: 83	Also Consider Outlet Tips, "Megaphone Effect" My 72 C20 had glasspacks when I got it. I thought it sounded pretty good. Then I put on a new exhaust system with 2 chamber flowmasters (40 series). It sounds much better with the flowmasters than it did with the glasspacks. One of the big differences in sound I have learned about is the size of megaphones if they are used. The exhaust shop explained this. We all know how a voice megaphone amplifies sound. I put on tips that are larger than the rear pipe when I put the flowmasters on the C20 truck. They work like voice megaphones and the sound waves are allowed to expand as they go from the tailpipe into the larger diameter magaphone tip before they leave the vehicle. Exhaust sound is louder than with same diameter exit tips. My recent K20 has the same flowmaster 40s as the C20 but with smaller outlet tips. There is a difference in how they sound. The K20 is a little quiter than the C20, even with the same pipes and mufflers. If you want louder, you can use tips that are a little or much larger than the tailpipe diameter and get more sound. Or just keep the tips the same size as the pipe and the sound will not amplify beyond what is governed by the muffler and pipe choices. I'm not trying to be a scientist, or positive that what I observe is the only truth, but what the muffler guys told me agrees with what I hear and how I know voice megaphones work. __________________ 72 C20 3/4 Custom Camper 94 Roadmaster Estate Wagon

01-16-2004, 02:02 PM	#11
melloyello Registered User Join Date: Nov 2002 Location: Spokane WA Posts: 66	i have glasspacks they are noisy but kinda nice if ya wanna bug the soccer mom in the minivan next to you as shes yackin on her cell phone and puttin on her make-up instead of paying attention to the road __________________ 67 C/20 camper special 350

01-16-2004, 02:39 PM	#12
gotmud Registered User Join Date: Oct 2003 Location: Cumming, Ga Posts: 234	What size of inlet and outlet did the 68 Chevy 307 come with? I assume I want the inlet to go over the pipe and then c clamp it on. __________________ Glenn Cumming, Ga (68 C/10 Fleetside LWB 307 (64 C/10 Fleetside Shorty Custom 350, with 73 donor parts aplenty) (2001 Porsche Boxster S - 168 MPH of fun) (2005 Chevy Avalanche Z71 1500)

01-16-2004, 02:54 PM	#13
shuttermutt Don't say "Oops!", Doctor Join Date: Nov 2003 Location: Houston, TX Posts: 677	I believe the factory small blocks used 2-inch, didn't they? __________________ 'Mutt 1968 CST LWB: R.I.P. 1967 Chevelle: TPI 454 beast 1967 C10 SWB: Claimed when Bumpster didn't put it on his list

01-16-2004, 03:06 PM	#14
CPNEJR Registered User Join Date: Sep 2003 Location: Franconia,N.H. Posts: 1,029	Yeah all the small-blocks are 2 in. stock size __________________ (Only) Member of the CPNE Fan Club Aint that the truth 67 C-10 350 with 3-speed tranny and 308 gears swb step 82 Z28 Camaro 355 small block over 350 hp and a borg warner super t-10 (blown engine) 72 Chevy K20 Suburban (future project) 70 Chevy K20 now 68 GMC K2500 2003 Chevy 2500hd ccsb 4X4 (daily driver)

01-16-2004, 03:38 PM	#15
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	i bought bargin turbo mufflers at a local auto parts for about $20 each i've got better things to do with my money than to try and impress people with overpriced mufflers __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY



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01-16-2004, 03:46 PM	#16
kaycee Registered User Join Date: Jan 2000 Location: Wyoming USA Posts: 2,449	Yeah what cdowns said __________________ 2001 Silverado K-1500 2005 FXDWG stage3 69 CHEVY Short/Step 327/4L60 373 posi 63 IMPALA 327

01-16-2004, 03:54 PM	#17
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	Defenitly flows! I have had both and i like the Flows 10x better! __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

01-16-2004, 05:01 PM	#18
SWEET7T Try spinnin 4 rear tars Join Date: Sep 2003 Location: Salt Lake City, Utah Posts: 757	Flowmasters!!! __________________ SWEET7T 1970 C10, 2wd, LB, 307/TH350/3.08. PS, PB

01-16-2004, 06:54 PM	#19
Slammed67 Progress = 0% Join Date: Nov 2001 Location: Kansas City, MO Posts: 2,108	Neither. Dynomax. __________________ Jason - '67 GMC swb \| '57 Bel-Air 4dr hardtop \| '56 210 4dr Wagon \| 2000 GMC Sierra

01-16-2004, 07:36 PM	#21
Martin64 Registered User Join Date: Oct 2003 Location: Yuma, Az Posts: 477	I have glass packs with 2 1/2" pipe and they are pretty loud. I like it but I'm not so sure how legal they are. One thing for sure is the soccer moms don't like 'em. __________________ Martin Gibson USAF Retired 1964(-ish) C10

01-16-2004, 08:29 PM	#22
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	HOOKER AREO CHAMBERS HOOKER AREO CHAMBERS HOOKER AREO CHAMBERS

01-16-2004, 08:35 PM	#23
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Flowmaster - had them on my last 2 trucks - great mufflers. Shawn __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

01-16-2004, 09:11 PM	#24
ckenwright Registered User Join Date: May 2003 Location: Phoenix, AZ Posts: 104	Dynaflow will out flow anything you can find, FlowMasters have a reputation for the welds coming loose and choking the exhaust. Glass Packs do not flow very well at all and are probably the worst decision you could make.

01-16-2004, 09:16 PM	#25
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	I just got two new flowmasters delivered for 91.98 here is the link where i got mine he has them in most inlet outlet configuration and sizes. If this auction isnt the size and conifg your lookin for he has links for the other styles of two chamber flows http://cgi.ebay.com/ebaymotors/ws/eB...tem=2454453908

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