Cats question

[76Blue_Beast]

Does anyone know if cats came stock on a 76 gmc sierra grande c20 ?May be a stupid question but this is something that I was asked buy a muffler shop and their store regulations. Sorry if it is stupid question to some of you. Thanks!
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[terryj]

I may be wrong, but I think that this only applied to California models, I know here in Oregon, C20's and greater didn't have all the emissions stuff on them.

[grs]

The muffler shop should know. If they don't know then find another shop.

[babyJay]

Originally Posted by grs

The muffler shop should know. If they don't know then find another shop.

my thoughts exactly.

I would venture to guess NO!

[donut]

Does the gas gauge say "unleaded fuel only"?
The C-30 in my sig didn't have cats.

[Junqueboi]

Originally Posted by donut

Does the gas gauge say "unleaded fuel only"?
The C-30 in my sig didn't have cats.

True statement (unless the cluster's been changed!) The muffler shop should know better. If the filler neck allows a diesel gas pump hose into it, it's HD; if it has the restrictor (with the little flapper), it's LD.

LD trucks have 'CATALYST' on the underhood emission label.

HD emission trucks typically have the emission label on the air cleaner while LD emission trucks have it on the radiator support. They may not have started doing this until the '77 or '78 model year though.

I'd be very suprised if any 70's era C20 was a LD emissions truck, especially the '75 & '76 model years. Some time in the 80's the Green Police raised the GVWR requirement for HD emission status so it was a little tougher to get a cat-less truck.

For example, I have an '86 C20 (305/700R4) truck that's LD emissions and an '86 C25 (350/THM400) that's a HD emissions truck with factory catless dual exhaust. They are both red but the C25 has a higher GVWR (and it's a much better vehicle).

[76stepsidechevy]

my 76 K10 had no cats from the factory and its a big 10. That was still a year where 3/4 ton and up didn't need cats.

[76Blue_Beast]

So mine is technically a c25 I think as its a GMC. It is 3/4 ton too but I really think someone had pieced the truck together. However it says Sierra Grande in the cab but that is all I really know :-( . Im just trying to get to know her better seeing how we've been together for almost 3 years. Hey for 900$ I wasnt complaining at all. Virtually rust free but one spot; drivers side first step into the cab a little is there.

The thing was I asked the iddiot at Midas or their other competitor near my house if they do custom work. I said I was thinking maybe straight pipes or something and that is when we got into their policy of if it came with cats they have to do cats. I'm going to bring it else where anyway but I wante to punch this idiot anyway. I hate cocky people like he was to me. Thanks for the input guys! God I love this site; sooooo helpful with everything possible.

[78 Big10 454]

I agree with the fellow board members about referring this question to a local muffler shop. They should have a comprehensive manual which specifies the exhaust components by year, make and model.

If it makes you feel any better, I'd bet my bottom dollar your truck did not come with cats from the factory. Here, in the Republik of Kalifornia, the smog police first mandated cats for half-ton pickups for the 1978 model year. You win, but I lost...

[76Blue_Beast]

Oh that sucks Im in Seattle and past 84 I believe or 85 youre good with emissions! Thats why I want something fun and loud!

[donut]

I do agree with everybody else, find another shop.
(imo, the "chains" define custom exhaust as putting a Mustang muffler on a Camaro. Back in the 80's I couldn't convince the tech at a Midas that my '68 Impala didn't have cats.)

I don't think that your truck had them. Gas gauge was the easy "proof". If gauge had nothing printed on it, you could point to it and say "see, no unleaded" ergo no cat.

[motornut]

don't know ? i guess in about 30 years they never really fixed one .....
I'd go somewhere else

[Cheapster]

Over 6000 gvw before 78 was considered heavy duty, after 78 they up'ed it to over 8000 gvw. My shortbed is 6200 and has no cats and came from Cali. Only thing my truck has is a smog pump, no EGR or cat.