dual glasspacks on a 1994 K1500

[motive power]

I was lookin into welding myself up a dual glasspack setup for my 350 and taking out the cat but i also thought that before i go do that i should get an 18" glasspack and try it out. i like loud, and i'm really REALLY tempted to take off my cat and have the true duals. i'm just not sure if i should go that route just yet. anyone have any insight for me? how would a 18" or even 12" sound? I was lookin into the trush series too.

[Droeder10]

I have dual 18" glasspacks on my truck with the cats still on and they are pretty loud..they sound very good too once youve had them on for a while. I cant remember what kind of glasspacks they are though.

[PA.REDNECK]

Shorter glasspacks = louder, get the shortest one you can if you want the loudest, I think somebody said cherrybomb makes an 8" one, not sure tho

[motive power]

i think i'm gunna go with a thrush, i'm gunna look into the shortest one they make. my buddy just welded true duals with glasspacks onto his f-150 and i love the sound.

[motive power]

by the way, I dont have dual pipes. just a Y-pipe before the cat. i'm just thinkin of cutting the muffler off and welding on the glasspack. i dont like some of the other mock ups i've seen with all the clamps and everything. any thoughts on welding vs clamps?

[oldred93]

Shorter glasspacks = louder, get the shortest one you can if ypu want the loudest, I think somebody said cherrybomb makes an 8" one, not sure tho

That was me, I think 18in Cherry Bomb glasspacks would sound good, 8in ones would be a lil obnoxious. IMO

[oldred93]

These are all the same truck with 16in Flo Pro Glasspacks. Things fackin loud!
http://www.youtube.com/watch?v=uAaPjRnGDOI&feature=relmfu
http://www.youtube.com/watch?v=8k_ZT1TmVsY&feature=relmfu
http://www.youtube.com/watch?feature=endscreen&NR=1&v=LZ9z8gALCXE

This one aint to bad either
http://www.youtube.com/watch?v=ykI1c7zkt-w&feature=related

[motive power]

http://www.youtube.com/watch?v=b51ZOGfMv7g
thats what i'm goin for i guess. just a single glasspack with the cat. gunna switch it up down the road though :D my neighbours are gunna love me!

[motive power]

anywho, what materials do i need for the single glasspack? i know i need to take a better look at everything, measure my pipes, check to see what the inlet/outlet is. should be easy. I also just looked at an older post and it said that the pipe size after the factory cat on a 1992 350 is 2 3/4" ..... would that be the same size on my 1994 350? i'm thinkin it is.

[silverado_lover]

Here's a rev to 2500 RPM for ya...


http://www.youtube.com/watch?v=bGz86uHr2gA

[oldred93]

http://www.youtube.com/watch?v=b51ZOGfMv7g
thats what i'm goin for i guess. just a single glasspack with the cat. gunna switch it up down the road though :D my neighbours are gunna love me!

o my bad when you said dual glasspacks, I thought you meant true dual. Well having a cat and a glasspack on just a single pipe isnt loud at all. Take the cat off and it would sound nice.

This is what I might do for my truck
skip to 1min to hear
http://www.youtube.com/watch?v=zNESCYBh2tM

[motive power]

ahhhhhk. i dont have the mechanical done on it yet but after i get it on the road in the next couple weeks i'm puttin on a cold air intake and takin out the cat to put the glasspack in. maybe put a Y-pipe and have fake duals haha.

[oldred93]

the video I posted has that setup no cat to a glasspack, y pipe after glasspack to duals. Save yourself the money and don't buy a HOT air intake, just modify the stock one. It costs about 5 dollars and brings in cold air=good not hot=bad.

[motive power]

how would i modify it? did you weld your glasspack in?

[oldred93]

go to the performance section of the forum and scroll down and look at the sticky threads for TBI's. I can't find the pics of mine that I modified. I would weld the glasspack on yes.

[Powerofv-8]

Taking the cat off will rob ur low end torque yes it will make it louder but the performance loss is not worth it

[hawkeyez71]

I have 3in to a 2.5in y then 2.5in back to 3.5in tips with two 18in glass packs and no cats and love the way it sounds except when we pulled the cat we couldn't get the new pipe to crush down enough and i have a exhaust leak to weld up nowhttp://www.fullsizechevy.com/forum/images/icons/icon8.png

[Powerofv-8]

Hawkeyez71 u have the 350 in it right

[hawkeyez71]

yes its the 350 TBI

[Powerofv-8]

I was letting u know that since u have no cats on it eventualy the engine is gunna fail on u cuz the 350 needs back pressure like i said earlyer with out back pressure u will be robbing the performance of the engine

[oldred93]

I was letting u know that since u have no cats on it eventualy the engine is gunna fail

:banghead:

[Powerofv-8]

Please tell me y u are banging ur head the 350 tbi has to have back pressure if now the low end torque will go down drasticaly in less u have some other way of creating back pressure

[Powerofv-8]

The new LS-1 engines especially need backpressure for low end torque and performance. Also for fuel economy. I beleive it has to do with the design of the heads and may tie into the EGR system. The Vortech 305's and 350's also needed this more than the older TBI engines which still require some to maintain the low end. Think of an engine as an air pump, air is brought in, mixed with fuel, ignited and then sent out the exhaust. An exhaust that flows too freely will have the air going out faster than the engine can take in. With todays computer controlled, emissions legal, more efficient engines they need that extra back pressure to maintain performance. Older carbuerated engines that did not have to be kept as clean or efficient can perform better with less backpressure.

This is a quote from another forum

[LT1/TA]

I don't doubt the back pressure theory but my 94 TBI pulls the same with out the cat as it did with the cat.

[LT1/TA]

I have a single 16" Glasspack 3" in/out then Y's to 2.5 duals with 3.5"x16" tips and it sounds great to me.I don't know what brand the Glasspack is but my guess would be a summit brand.I cut the Glasspack and dual tail pipes off of a 92 F150 longbed at the junkyard.