right now i have an F250 4x4 with a 360 in it with the stock manifolds running into some knock off mufflers which run out before the tire. Would running glass packs make the truck sound meaner?

 

Yes, yes it would. However there are many mufflers that can too.

 

thanks just wanted something quick and cheap to get it goin good

 

Be advised, glass packs are NOT free flowing, so if you want performance and gas mileage, look at a real muffler instead.

 

so what would you suggest

 

http://www.youtube.com/watch?v=oz2rJCRLvKE

 

Please be advised that the term "glass packs" would include:

Allied
Edelbrock
Borla
Magnaflow
Hooker

All of which use packing material which although is not fiberglass (as no one has used in 20 years), they each use a sound material absorbing design. Even conventional "glass packs" are proven in flow testing to out perform many of the so-called "Free Flowing Real Mufflers". For reference, WyoTech, Hot Rod Magazine have numerous published articals on this. On the net, please read:

broaderperformance.com/muffler_flow_tests.htm (Independently tested cfm flows of the more popular mufflers, glasspacks and resonators.

http://www.popularhotrodding.com/eng...../index1.html (this is an indepth artical that tests not only the mis-conception of flow demand but also how placement of a muffler (a glass pack in this dyno test) can actually "fool " the system into thinking that it is essentially a straight pipe.

I have listed here a muffler shootout test done by CAR CRAFT:

The Mufflers
MAKE MODEL Part No. COST
SUMMIT Turbo 630125 $14.75
THRUSH Magnum Glasspack 24214 $16.50
THRUSH Boss Turbo 17718 $23.95
HOOKER Competition 21006 $25.95
DYNOMAX Super Turbo 17733 $28.50
DYNOMAX Race Magnum 24215 $31.95
HOOKER Super Competition 21106 $35.95
SUMMIT Fully Welded 630325 $38.69
FLOWTECH Afterburner 50322 $39.95

MUFFLER FLOW TEST

MUFFLER Flow at 28-in H20
DynoMax Race Magnum 528.64 cfm
Thrush Magnum Glasspack 507.40 cfm
Summit Fully Welded 343.38 cfm
Flowtech Afterburner 342.20 cfm
DynoMax Super Turbo 333.94 cfm
Hooker Competition 232.46 cfm
Hooker Super Competition 320.96 cfm
Summit Turbo 331.16 cfm
Thrush Boss Turbo 297.36 cfm

MUFFLER Idle dB WOT dB
DynoMax Super Turbo 89 123
DynoMax Race Magnum 94 133
Flowtech Afterburner 92 124
Hooker Competion 92 122
Hooker Super Competion 90 125
Summit Turbo 89 124
Summit Fully Welded 92 125
Thrush Boss Turbo 90 123
Thrush Magnum Glasspack 92 128

DYNO TEST
All mufflers were dyno-tested on a 355-cube SBC with 10.0:1 compression, Air Flow Research 190 aluminum heads, a CompCams 292 hyd. a Victor Jr. intake, a Holley 750-cfm double-pumper, and 1 5/8 Headman headers.


MUFFLER HP TORQUE 2,500-6,000rpmAverage
Hooker Competition 397.4 381.1 286.8hp/351.9 lb-ft
Thrush Boss Turbo 407.1 384.9 292.1 hp/357.5 lb-ft
DynoMax Race Magnum 409.5 394.3 298.8 hp/366.9 lb-ft
Flowtech Afterburner 409.7 391.2 294.8 hp/361.7 lb-ft
Thrush Glasspack 409.5 389.8 297.7 hp/365.3 lb-ft
Summit Turbo 411.5 386.3 291.5 hp/357.4 lb-ft
DynoMax Super Turbo 412.7 387.2 292.6 hp/358.6 lb-ft
Hooker Super Comp 413.8 387.2 292.8 hp/359.0 lb-ft
Summit Fully Welded 415.4 390.7 295.6 hp/362.4 lb-ft

While there are mufflers that will out flow a glass pack design, it also depends on the design. Does the glasspack use "louvers or perforations" - Louvers reduce the flow by as much as 50% but Allied resonators (that sell for $20-$40) each and available at any muffler shop) installed backwards in independent test flowed 90%+ of a "race spec muffler". Others using other brands consistantly showed similar results.