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Old 11-18-2021, 09:01 AM   #1
GOPAPA
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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 ?
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Old 11-18-2021, 09:22 AM   #2
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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...
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Old 11-18-2021, 11:14 AM   #3
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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.
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Old 11-18-2021, 12:54 PM   #4
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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.
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Old 11-18-2021, 02:08 PM   #5
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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

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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?
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Old 11-18-2021, 04:31 PM   #6
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Re: Truck needs a new catalytic converter (help needed)

i just eliminated mine no emmissions in NJ for a truck that old
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Old 11-18-2021, 06:37 PM   #7
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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.
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Old 11-18-2021, 07:31 PM   #8
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Re: Truck needs a new catalytic converter (help needed)

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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.
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Old 11-18-2021, 08:13 PM   #9
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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.
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Old 11-18-2021, 08:41 PM   #10
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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.
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Old 11-20-2021, 04:29 PM   #11
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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.
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Old 11-20-2021, 09:04 PM   #12
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Re: Truck needs a new catalytic converter (help needed)

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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?
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Old 11-21-2021, 09:09 AM   #13
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Re: Truck needs a new catalytic converter (help needed)

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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 ??)
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Last edited by GOPAPA; 11-21-2021 at 09:23 AM.
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Old 11-21-2021, 10:29 AM   #14
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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..
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Old 11-21-2021, 10:53 AM   #15
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Re: Truck needs a new catalytic converter (help needed)

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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
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