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Exhaust Kit Needed for 1977 but none found

ZombieK5

ZombieK5

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I have spent the better part of two days researching exhaust kits for the 1977 Blazer I recently purchased. This truck has a 468 Big Block Chevy installed which creates one of the issues I have come across. From my understanding the 468 is based upon the 454 block. I am hoping a big block exhaust kit for an 80's model K5 will work...but I doubt I'll be that lucky? Would the 1977 exhaust system route the same way as the 80's versions?


What I am seeking is information from any members that know of any other model year exhaust kits that would fit the 1977. I don't mind paying for good stainless pipes but I'm hoping to find one that is modestly easy to install. I have no issue fabricating my own hangers and I have no tissue cutting or tack welding tubes. Does anybody know of a kit that would fit the 1977? Currently it has headers from an unknown manufacturer. I am planning to put on new headers. The current headers flow into a horribly designed down pipe that leads to 2 exceptionally loud mufflers. The mufflers do not have pipe that lead to the traditional exits behind the rear wheels. The Mufflers currently have about 12 in of pipe that terminate near the midsection of the vehicle. I have found that this causes exhaust fumes to leak into the vehicle cab at idle.

I will post photos as soon as I am able to get under the truck.

Any interchangeability or advice is welcome. I'm looking for some mild Flowmaster mufflers and a modest header that will last. With the 468 engine I am assuming I will need at least two and a half inch exhaust pipe. I have searched the forums but have not found any topics on this exact subject. Local exhaust shops won't touch it because of the catalytic converters missing even though I tell them it DIDN'T come with cats. Grrrrrr

Thanks for any help

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The issue I can see an exhaust shop having is your k5 is most assuredly doing it's best to look exactly like a 91 K5 which would have had cats. If you want a kit, look one up for a pick-up and shorten/modify as needed. A 468 isn't based on a 454, it is a 454 that has been over-bored by .060" when it was rebuilt. No big block was ever offered in a K5 from the factory. Easy to swap though, which is why they are out there.

I would skip the 2.5" stuff and head directly to 3"
 
That's what I meant by "based on a 454," however... That makes sense to look for a pickup version. Only question would be about the cross members and how simiar that are or should I say how different they are.

The local shops know its a 1977 but the 20-something techs they employ "know it all" and won't accept the ideaine didn't come with cats.
 
tRustyK5 said:
The issue I can see an exhaust shop having is your k5 is most assuredly doing it's best to look exactly like a 91 K5 which would have had cats. If you want a kit, look one up for a pick-up and shorten/modify as needed. A 468 isn't based on a 454, it is a 454 that has been over-bored by .060" when it was rebuilt. No big block was ever offered in a K5 from the factory. Easy to swap though, which is why they are out there.

I would skip the 2.5" stuff and head directly to 3"
Click to expand...

Found this...thoughts?

https://www.holley.com/products/exh...ct_fit_pipe_kits/prebent_tailpipe/parts/15803

Or

https://www.holley.com/products/exhaust/exhaust_systems/flowtech/parts/64000FLT
 
Stuff for 73-87 pick-ups can be easily modified, so yeah those would work. If it were mine I'd go with 3" though.
 
I've bought the "pre-bent" kits for K10/20/30 trucks and used them on the K5 frame before. I've also done the kit on the K10

On the last go round, I bought the box of bends and straights and did the work.
Takes a lot longer, much happier with the layout doing it myself
Mine is 2.5" duals on a healthy small block, so at least that big for duals and 3" for a single for a 468"
Single can be difficult due to the cross over and interference. Duals potentially compromise the fuel on that side of the frame
All reasons to do it yourself
Just my $.02

https://www.bing.com/shop?q=bends+and+tubes+exhaust&FORM=SHOPTB
 
tRustyK5 said:
Stuff for 73-87 pick-ups can be easily modified, so yeah those would work. If it were mine I'd go with 3" though.
Click to expand...

So far I have not been able to find a kit with 3 inch tubes. There are several kits with 2.5" but none with 3". I think I will get one of those kits as well as one of the kits with random bends and try and Frankenstein the whole thing. I guess I need to get a pipe expander from Harbor Freight in case I need to create a female end. I would also have to think that if I went with duals that the 2.5" should be okay on the 468 big block.
 
Bent77 said:
I've bought the "pre-bent" kits for K10/20/30 trucks and used them on the K5 frame before. I've also done the kit on the K10

On the last go round, I bought the box of bends and straights and did the work.
Takes a lot longer, much happier with the layout doing it myself
Mine is 2.5" duals on a healthy small block, so at least that big for duals and 3" for a single for a 468"
Single can be difficult due to the cross over and interference. Duals potentially compromise the fuel on that side of the frame
All reasons to do it yourself
Just my $.02

https://www.bing.com/shop?q=bends+and+tubes+exhaust&FORM=SHOPTB
Click to expand...


Any chance you could send me some photographs of your exhaust layout? I'm interested in the hanger locations as well as the locations of the clamps.
 
ZombieK5 said:
Any chance you could send me some photographs of your exhaust layout? I'm interested in the hanger locations as well as the locations of the clamps.
Click to expand...
Outlets run down the outside of the frame to get away from the tank
 
Here is what I current have going on....

I just noticed I have an 02 sensor on the left side exhaust. I need to see where that goes.

20200308_181507.jpg

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20200308_181552.jpg
 
So I'm guessing it's carbureted at this point? That O2 sensor is just a plug if that's the case
 
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