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Carb changes when installing sidepipes

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redmist

Guest
I was told by my machine shop that sidepipes (with sidepipe mufflers) create a significant restriction over a free flowing conventional exhaust system. I find now that I am getting performance increases by leaning out my 1407 edelbrock carb as he suggested. Does anyone else who has made the conversion had a similar experience?
Thanks.
 

Tom Bryant

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1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
Exhausting subject

Redmist,

You will find that just about any major change to the exhaust will effect the carb mixture. Always a good idea to rejet or at least experiment with different jetting after installing headers or free flowing exhaust. Keep in mind that the original carb calibrations were a compromise for the best operation for the most circumstances. Your exhaust, intake mods, cam and head work, altitude where you live, and even today's temperature and barometer will effect optimum jetting.

Tom
 

grumpyvette

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Loxahatchee, FL, Palm Beach co
exaust

IT IS MOST LIKELY THAT THE CHANGE TO SIDE EXAUST MADE YOUR ENGINE MORE EFFICIENT AT PULLING THE SPENT EXAUST GASSES OUT OF THE CYLINDERS(BETTER CYLINDER SCAVAGEING ) THIS WOULD CAUSE THE CARB, TO GET A STRONGER SIGNAL(GREATER SUCTION ) THIS WOULD CAUSE THE CARB TO NEED DIFFERENT JETTING AND VACUUM SETTINGS LIKE BILLAGROOM AND 59TOM SAID! :D WHEN i PUT SIDE PIPE HEADERS ON MY 496 CID 68 VETTE i HAD TO CHANGE TO LEANER PRIMARY AND RICHER SECONDARY JETS :D
 

JCL

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1979 "383" TORCH RED- 2000 Torch Red "FRC."
SIDEPIPES

GRUMPYVETTE. CURIOUS TO KNOW WHAT MUFFLER SYSTEM YOUR USING ON THAT BIG BLOCK. HOWS THE SOUND!! JCL
 

grumpyvette

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Loxahatchee, FL, Palm Beach co
headers

the headers on that car( I sold it a little while ago to get my 1985)(kept the engine) which Im going to put a big block in too! were hooker super comps #hoo-2222-1 with 4" full length side tube, It uses slip in inserts(its very loud but pre-1976 cars did not need to go through inspection and I only used them to get to the track) and I never got a noise ticket either, (they came out as soon as I got to the track).and yes as long as I was carefull not to get the engine over 1500rpm(drove in top gear alot) I got by even in traffic :D
 
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redmist

Guest
Thanks for all the input. To clarify I am using the Hooker sidepipes Grumpy is refering to with the slip in mufflers. With the mufflers in the sound is very pleasant, loud when you get on it, purrs when cruising. Without the mufflers it sounds NASTY (read GREAT!!), but too loud for avoiding the scorn of neighbors or the attention of the noise police. I know that without the mufflers there is not a restriction problem I am concerned though about the effect of the mufflers. I'm going down to .104 jets in the primary and .098 in the secondaries and see what happans.
 

Tom Bryant

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1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
headers

I had the sidepipe headers on my '67 427. Click on the URL icon below and go to the "Other cool stuff" page to see it. I only had it out on the road a couple times with the mufflers out and I couldn't see a big improvement in performance. No doubt there was some and the grin factor was definately higher. You would need to put you car on a dyno and run it with and without to know the truth. Check the links to dyno shops on the CAC or the yellow pages.

Chevrolet sold this system, made by OK Kustom Headers, through their parts depts. in the '70s for the Corvette racers. Can't be too bad.

Tom
 

JCL

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SEVILLE,OHIO
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1979 "383" TORCH RED- 2000 Torch Red "FRC."
"ALOT OF RESTRICTION"

REDMIST.I THINK YOUR GOING TO GET RESTRICTION WITH EITHER THE CONVENTIONAL SYSTEM AND FOR SURE THE HOOKER MUFFLER SET UP!! I BOUGHT THE REGULAR HOOKER MUFFLER AND WHEN I LOOKED INSIDE AND SAW THE SMALL AREA FOR EXHAUST TO FLOW OUT, THEY WENT BACK TO SUMMIT! WAY TO RESTRICTIVE. I KNOW I SAW A POST ON ONE OF THE OTHER FORUMS WHERE A GUY DID DYNO WITH AND WITHOUT AND I THINK THE LOSS WAS 95HP WITH HOOKERS MUFFLER! TEST WAS ON A BIG BLOCK. NOW UNLESS YOU'VE GOT HP YOU CAN AFFORD TO LOSE.....
 

grumpyvette

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mufflers

yes the hooker slide in mufflers kill a bunch of horse power but they do let you drive on the street, and without the slide in mufflers installed this setup runs GREAT AND IT ONLY TAKES 10 MIN. to take them out to run 10s with the right motor :D
 

Jack

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Florence, SC (Timmonsville SC)
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71 War Bonnet Yellow VERT 71 BH Blue CPE (SOLD)
two slip-in designs

It's my understanding Hooker offers two different slip-in designs for their sidepipes ... one is a glass pack ... the other is a steel chambered/louvered (when I ran steel chambered/louvered inside Harley drag/straight pipes, they were called "baffles").

BTW, anyone remember the infamous roadside video of the screaming South Carolina Highway Patrolman dragging & macing lady out of her car? He got it honestly ... his dad was a trooper too ... carried around a coat hanger; bent just to reach inside drag pipes ... to detect presence of baffles. Thanks be to God ... the Beckwith family is no longer w/ SCHP.
JACK:gap
 

Tom Bryant

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1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
side pipes

Mine weren't Hooker. They were either Doug's or OK Kustom. They had a plenty big passage through them and you couldn't hear the radio above 25mph. Loved them.

Tom
 

JCL

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Location
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1979 "383" TORCH RED- 2000 Torch Red "FRC."
BEST OF BOTH WORLDS

59Tom. Tom i guess what i was trying to get at it would be nice to have both worlds. Something that would not restrict the motor, and be reasonably quiet. Quiet in the terms of it still has to have that corvette sound!! Thanks, JCL :cool
 
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redmist

Guest
Follow up

Based on the good advice here I order the "glass pack" inserts for the Hooker pipes. I currently have the "reverse flow". They were pretty cheap (glass pack) at $129 a pair from Summit. I'll let the group know how the noise and perfromance change and if a jeting change is needed.
I completed the secondary jet change on the 1407 edelbrock to a .098 and changed the primaries to a .107 and 71 by 47 metering rods with the silver springs. Bingo. Scary fast and 6500 rpms. I am hooking up a air/fuel ratio monitor and see if the SOP tuning matches the ideal chemical one.
 
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79blueshark

Guest
I have the Hooker Sidepipes with the Glass packs on my small block and really didn't see a big difference in power with or without the mufflers. My problem was I got the things ceramic coated. That caused a 3 hour per side installation of the tubes onto the headers, and that was using a 1x2 and a 3 pound sledge. What really gets my crawl is the damn things still leak and the clamp. I would have to say I am envious that you guys can take yours on and off easily.
 

JCL

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Joined
Feb 23, 2001
Messages
56
Location
SEVILLE,OHIO
Corvette
1979 "383" TORCH RED- 2000 Torch Red "FRC."
SIDEPIPES

79BLUESHARK. IS YOUR MOTOR STOCK OR DO YOU HAVE ANY MODIFICATIONS?? E-MAIL ME. THANKS,JCL
 
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redmist

Guest
Update

Pulled the reverse flow muffler inserts and installed the Hooker glasspack inserts BACKWARDs. Picked up at least 75 Hp and it revs a lot easier. I capitialized backwards because during my research I read an article that said that the punched in scallops on the inside of the mufflers restrict airflow 50% if they face the front. Sounds real sweet too.
 
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fasterthanu

Guest
Header Sidepipes

Do you know the part number for the glasspacks you ordered? I too have the header/sidepipes and notice a restriction. Also, you said you installed them backwards.... Feel the difference? I can take the pipes off easily enough, how do I take the glass packs, or baffles out? Thank You.
 
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redmist

Guest
Sidepipes

Hi, this applies to the Hooker Header sidepipes and not the OEM or aftermarket OEM imitations.
The glasspack mufflers you can order right from Summit Racing. Hooker only offers two versions of the inserts, the reverse flow mufflers and the glasspacks.
They come out easily just remove the sidepipe from the header turn it upside down and tap on on a peice of wood placed on the ground. They should just pop out. If not check to make sure someone didn't tack weld the edges to the inside of the sidepipe or heaven forbid put a rivet or a screw through the sidepipe into the muffler.
The glasspacks are reversed when the perforations on the inside of the glasspack are open to the back of the car. Yes it makes a huge difference.
I recently took my glasspacks out and put in some 3 ring baffles sold by Car Chemistry, Inc. I haven't fired the car up yet so I can't tell you how they sound or perform.
 
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fasterthanu

Guest
Redmist, are you going to fire your car up soon? Really would like to know how it sounds. I am puttina 480hp small block in. Would love to hear how it handles the hp... Is there a link for the 3 ring baffles you bought? Also, is this the part number for the glass packs for summit.. HOK-21021 So, when I get these, just push them in the opposite of the directions, right?
 
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redmist

Guest
www.carchemistry.com

Here is the link. I should be starting it up tomorrow. Did some extensive mods over the winter and just tying down the loose ends.
With a 480hp small block you are definetly going to need to let that sucker breathe.
I'm also toying with installing a crossover pipe at the end of the header. I put oxygen sensors there and I'm going to unscrew them and temporarily install a pipe between them and see if it makes a difference. I'm putting out around 420 hp and it still feels like it needs a less restrictive exhaust.
Yes that is the summit part# for the glasspacks. I don't recall if there are any instructions. Just look down the pipe at the "scalloped" openings. You want the openings to face the back of the car.
 

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