The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 11-18-2021, 09:01 AM   #1
GOPAPA
"Tail Gate Best Seat In House"
 
GOPAPA's Avatar
 
Join Date: Oct 2007
Location: Nampa Idaho
Posts: 7,350
Truck needs a new catalytic converter (help needed)

I find that what came on the truck new was a pancake converter and they run around $1100 ,, I really do not want to spend that much just to stay original . I only want to pass emissions and of course one that lasts
What have you all been replacing your cats with and also mufflers?

I am staying with single exhaust with two tail pipes ,with a good ol rumble sound . One cat and One Muffler ..What muffler do you recommend for a good sound / 1983 Chevy K10 350 V8 engine ?
__________________
When you learn a thing a day you store up smart.
GOPAPA is offline   Reply With Quote
Old 11-18-2021, 09:22 AM   #2
mongocanfly
Post Whore

 
mongocanfly's Avatar
 
Join Date: May 2015
Location: Alabama
Posts: 14,585
Re: Truck needs a new catalytic converter (help needed)

For mufflers on my C30, I used a set of magnaflow knockoffs..at the time they called them magflow..
Theyve since changed the name to maxflow, I think..got them off ebay..they're stainless..love the way they sound
We dont have emissions to worry about here.so I dont know about the cats...
__________________
Mongo...aka Greg

RIP Dad
RIP Jesse

1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598
Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334
Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563
2023 Chevy Z71..daily driver
mongocanfly is offline   Reply With Quote
Old 11-18-2021, 11:14 AM   #3
kwmech
Senior Member
 
Join Date: Mar 2003
Location: Colfax-California
Posts: 8,390
Re: Truck needs a new catalytic converter (help needed)

I don't think the older pellet convertors are available anymore, so going with a monolithic honeycomb shouldn't be a problem. Just order one in the pipe size you're running and splice it in. Try to mount it as forward as you can so it grabs more heat in the pipe.
kwmech is offline   Reply With Quote
Old 11-18-2021, 12:54 PM   #4
Loco83
Registered User
 
Loco83's Avatar
 
Join Date: Nov 2018
Location: Cali
Posts: 283
Re: Truck needs a new catalytic converter (help needed)

Went with a MAGNAFLOW high flow cat on my 83, switched to a larger 3" single exhaust system.
Loco83 is offline   Reply With Quote
Old 11-18-2021, 02:08 PM   #5
GOPAPA
"Tail Gate Best Seat In House"
 
GOPAPA's Avatar
 
Join Date: Oct 2007
Location: Nampa Idaho
Posts: 7,350
Re: Truck needs a new catalytic converter (help needed)

Quote:
Originally Posted by mongocanfly View Post
For mufflers on my C30, I used a set of magnaflow knockoffs..at the time they called them magflow..
Theyve since changed the name to maxflow, I think..got them off ebay..they're stainless..love the way they sound
We dont have emissions to worry about here.so I dont know about the cats...
Iwonder if they are called Magnaflow now like what Loco83 says below?

Quote:
Originally Posted by kwmech View Post
I don't think the older pellet convertors are available anymore, so going with a monolithic honeycomb shouldn't be a problem. Just order one in the pipe size you're running and splice it in. Try to mount it as forward as you can so it grabs more heat in the pipe.
I have a cross over and I would guess the Cat should be right after they two sides meet

Quote:
Originally Posted by Loco83 View Post
Went with a MAGNAFLOW high flow cat on my 83, switched to a larger 3" single exhaust system.
I Have 2 inch headers ,so do you think I should get a cat with 3 inch inlet and outlet to match up with the Muffler and Tail Pipe being 3 inch?
__________________
When you learn a thing a day you store up smart.
GOPAPA is offline   Reply With Quote
Old 11-18-2021, 04:31 PM   #6
old Rusty C10
Robert Olson Transport
 
old Rusty C10's Avatar
 
Join Date: Oct 2002
Location: recent transplant to NC USA
Posts: 20,261
Re: Truck needs a new catalytic converter (help needed)

i just eliminated mine no emmissions in NJ for a truck that old
__________________
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!!
old Rusty C10 is offline   Reply With Quote
Old 11-18-2021, 06:37 PM   #7
Dead Parrot
Registered User
 
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 2,478
Re: Truck needs a new catalytic converter (help needed)

Double check your state rules on such things. A lot of states drop emissions requirements once a vehicle is a certain age. Other states are really picky and want pretty much OEM as much as possible.

The pancake converters were rather poor flowing so if you still need a cat, one of the new honeycomb types would be better. Made that swap on an old 79 Camaro and gained 3 mpg.

Neither of my trucks need converters. The 75 came as a HD emission setup with no cats. The CUCV is a diesel.
Dead Parrot is offline   Reply With Quote
Old 11-18-2021, 07:31 PM   #8
GOPAPA
"Tail Gate Best Seat In House"
 
GOPAPA's Avatar
 
Join Date: Oct 2007
Location: Nampa Idaho
Posts: 7,350
Re: Truck needs a new catalytic converter (help needed)

Quote:
Originally Posted by Dead Parrot View Post
Double check your state rules on such things. A lot of states drop emissions requirements once a vehicle is a certain age. Other states are really picky and want pretty much OEM as much as possible.

The pancake converters were rather poor flowing so if you still need a cat, one of the new honeycomb types would be better. Made that swap on an old 79 Camaro and gained 3 mpg.

Neither of my trucks need converters. The 75 came as a HD emission setup with no cats. The CUCV is a diesel.
Darn! Idaho state law requires model year 1981 and newer gasoline and diesel-powered vehicles older than five years to be tested every other year.
__________________
When you learn a thing a day you store up smart.
GOPAPA is offline   Reply With Quote
Old 11-18-2021, 08:13 PM   #9
LT7A
Registered User
 
Join Date: Oct 2015
Location: PNW
Posts: 3,511
Re: Truck needs a new catalytic converter (help needed)

MagnaFlow metal matrix high flow catalytic converters have taken really good care of me. You'll get a little more sound out of it and a lot more flow. My cat back exhaust system is made by flowmaster and was the only one available back when I put it on. Very happy with the fit and the sound though. But I would search muffler in here, find some names, and then go online and listen to some clips and some YouTube videos to find what you want. Exhaust sound is very subjective.
LT7A is offline   Reply With Quote
Old 11-18-2021, 08:41 PM   #10
Loco83
Registered User
 
Loco83's Avatar
 
Join Date: Nov 2018
Location: Cali
Posts: 283
Re: Truck needs a new catalytic converter (help needed)

Quote:
Originally Posted by GOPAPA View Post
Iwonder if they are called Magnaflow now like what Loco83 says below?



I have a cross over and I would guess the Cat should be right after they two sides meet


I Have 2 inch headers ,so do you think I should get a cat with 3 inch inlet and outlet to match up with the Muffler and Tail Pipe being 3 inch?
Yes, yes and yes, my cat is mounted at the "Y" of the engine exhaust and it's 3" all the way back to a Flowmaster 40 3" inlet and dual 2.5 outlets dumped in front of the axle.
Loco83 is offline   Reply With Quote
Old 11-20-2021, 04:29 PM   #11
Pontiac1976
Registered User
 
Pontiac1976's Avatar
 
Join Date: Oct 2015
Location: Ottawa, Ontario, Canada
Posts: 750
Re: Truck needs a new catalytic converter (help needed)

Try looking up Walker re-placement Cat for your year, or Dynomax for the sport side of walker. (still pan cake) Or try 88-93 GM trucks to see what they replacing with at dealer. 94-99 I be leave have the lighter cat smaller.
__________________
1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.
Pontiac1976 is offline   Reply With Quote
Old 11-20-2021, 09:04 PM   #12
farmall
Registered User
 
farmall's Avatar
 
Join Date: Jun 2011
Location: Central OR
Posts: 653
Re: Truck needs a new catalytic converter (help needed)

Quote:
Originally Posted by GOPAPA View Post
Darn! Idaho state law requires model year 1981 and newer gasoline and diesel-powered vehicles older than five years to be tested every other year.
Do they enforce it?

What happens if you don't get sniffed?
__________________
1955 GMC 250 8 Flatbed
1971 C30 157" 350 4spd 10' Flatbed
81 GMC K30 CnC 9' Flatbed 454 T400
89 GMC Jimmy Stock https://67-72chevytrucks.com/vboard/...d.php?t=810958
71 LT1 Convertible, 72 Coupe
69 CJ5, 75 CJ6, 67 M715, 72 M35A2 Bobbed, 95 XLC2
farmall is offline   Reply With Quote
Old 11-21-2021, 09:09 AM   #13
GOPAPA
"Tail Gate Best Seat In House"
 
GOPAPA's Avatar
 
Join Date: Oct 2007
Location: Nampa Idaho
Posts: 7,350
Re: Truck needs a new catalytic converter (help needed)

Quote:
Originally Posted by farmall View Post
Do they enforce it?

What happens if you don't get sniffed?
I get a notice in the mail every two years to let me know I need to get a emissions test .. There are several places to get tested ,, the one I go to is a Chevron Service station and it cost last I went $11-- now it is $14 ,,it takes about 5-10 minutes to get tested and they send the results into the DMV .. I suppose the police are notified if you have not taken care of your vehicle if you do not pass.(never knew this happening ,,so just a guess )

Only two counties are the emission law testing places and 81 year vehicles and newer are under this law,, classics are most of the time not included ,,( I will maybe get my 83 under the classic title ??)
__________________
When you learn a thing a day you store up smart.

Last edited by GOPAPA; 11-21-2021 at 09:23 AM.
GOPAPA is offline   Reply With Quote
Old 11-21-2021, 10:29 AM   #14
mongocanfly
Post Whore

 
mongocanfly's Avatar
 
Join Date: May 2015
Location: Alabama
Posts: 14,585
Re: Truck needs a new catalytic converter (help needed)

Magnaflow mufflers was and is the original
Magflow was a cheaper $$ copycat version
Maxflow is the renamed version of magflow...
The magflow are all stainless..and from what we could see are identical to magnaflow, just a whole lot cheaper..I thought I would regret using them, but I didnt..actually bought another set for my current build..these are the 20in version..the ones on my C30 are 16in..
__________________
Mongo...aka Greg

RIP Dad
RIP Jesse

1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598
Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334
Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563
2023 Chevy Z71..daily driver
mongocanfly is offline   Reply With Quote
Old 11-21-2021, 10:53 AM   #15
GOPAPA
"Tail Gate Best Seat In House"
 
GOPAPA's Avatar
 
Join Date: Oct 2007
Location: Nampa Idaho
Posts: 7,350
Re: Truck needs a new catalytic converter (help needed)

Quote:
Originally Posted by mongocanfly View Post
Magnaflow mufflers was and is the original
Magflow was a cheaper $$ copycat version
Maxflow is the renamed version of magflow...
The magflow are all stainless..and from what we could see are identical to magnaflow, just a whole lot cheaper..I thought I would regret using them, but I didnt..actually bought another set for my current build..these are the 20in version..the ones on my C30 are 16in..
thx I copied this down
__________________
When you learn a thing a day you store up smart.
GOPAPA is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 04:02 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com