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Discussion Starter · #1 ·
My 1976 chevy 350 gasser has a single exhaust system, it uses a cross over pipe. I'm replacing the gasser with a 6.2 diesel engine. Will the 6.2 run with the old gasser single exhaust system?
 

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Yes, it will run with that exhaust if you get it bolted up. It won't perform very well at all, but it will run... :)

Once it is all installed and running you will need to invest in a good set of duals and mufflers. It will probably be rather powerless and run poorly with the single exhaust.
 

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A single exhaust will not be good for much.
 

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you could always put 3 or 4" on it single...thatd run just fine, come to think of it...3" single will be plenty big enough for a stock 6.2, it will never move enough exhaust to be restricted in a single 3"
 

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76chevyc10;1538929; said:
My 1976 chevy 350 gasser has a single exhaust system, it uses a cross over pipe. I'm replacing the gasser with a 6.2 diesel engine. Will the 6.2 run with the old gasser single exhaust system?
The single exhaust would work fine as long as you had a low-restriction muffler. But, where would you get a stock Y-pipe from? I don't think GM ever made one. Ford did. The stock exhaust system with the larger Ford 6.9 diesel is a Y-pipe hooked to a 2.5" single exhaust and one high-flow muffler. Same size as a 350 GM gas system. All the stock GM 6.2 diesel exhaust systems I've seen use dual 2.5 pipes and the two OEM mufflers that are actually 1.5" internally because of the silencer-baffle system. So, the stock 6.2 had an exhaust flow with both mufflers combined of 3.5 square inches of pipe-flow area. A single 2.5" exhaust has a 4.9 square inch area of flow - as long as the muffler is also 2.5" internally - which is actually more than the GM OEM dual exhaust.
There are aftermarket Y-pipes made for single-exhaust 6.2 diesel turbo systems but they are 3" diameter. If you had to buy an expensive Banks Stinger Y-pipe - and adapt it to your dual 2.5" pipes - seems the expense would negate any gain of using your original 350 gasser system.

A stock naturally aspirated 6.2 diesel - governed at 3600 RPM but pretty much useless past 2700 RPM - does not move enough air or exhaust where it needs the dual-exhaust. It one of the few things that GM did that was an "overbuild" - which is good. The dual system is more tolerant to the addition of aftermarket mufflers from places like NAPA that are highly restrictive and not intended for diesels. If you install the wrong mufflers it can retain too much heat at the cylinder-heads - especially when trailer towing.

On my 85 Ford F250 - with the 6.9 diesel and stock single 2.5" exhaust. I ran it all summer with no exhaust except for the remnents of a rusted out Y-pipe. It didn't have any more power than it did with the new system I finally got around to installing.
 

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jdemaris;1540202; said:
The single exhaust would work fine as long as you had a low-restriction muffler. But, where would you get a stock Y-pipe from? I don't think GM every made one. Ford did. The stock exhaust system with the larger Ford 6.9 diesel is a Y-pipe hooked to a 2.5" single exhaust and one high-flow muffler. Same size as a 350 GM gas system. All the stock GM 6.2 diesel exhaust systems I've seen use dual 2.5 pipes and the two OEM mufflers that are actually 1.5" internally because of the silencer-baffle system. So, the stock 6.2 had an exhaust flow with both mufflers combined of 3.5 square inches of pipe-flow area. A single 2.5" exhaust has a 4.9 square inch area of flow - as long as the muffler is also 2.5" internally - which is actually more than the GM OEM dual exhaust.
There are aftermarket Y-pipes made for single-exhaust 6.2 diesel turbo systems but they are 3" diameter. If you had to buy an expensive Banks Stinger Y-pipe - and adapt it to your dual 2.5" pipes - seems the expense would negate any gain of using your original 350 gasser system.

A stock naturally aspirated 6.2 diesel - governed at 3600 RPM but pretty much useless past 2700 RPM - does not move enough air or exhaust where it needs the dual-exhaust. It one of the few things that GM did that was an "overbuild" - which is good. The dual system is more tolerant to the addition of aftermarket mufflers from places like NAPA that are highly restrictive and not intended for diesels. If you install the wrong mufflers it can retain too much heat at the cylinder-heads - especially when trailer towing.

On my 85 Ford F250 - with the 6.9 diesel and stock single 2.5" exhaust. I ran it all summer with no exhaust except for the remnents of a rusted out Y-pipe. It didn't have any more power than it did with the new system I finally got around to installing.
Excellent input.

Suggestion - each time someone inquires about exhaust setups, repost that response, similar to a FAQ.

3" or even 5" duals would look good, but a 3" single like the 6.5TD would be as efficient as a dual 2.5" system, which 2.5" is entirely suitable for the 6.2na without kinks, sharp bends, and multiple bends.
 

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4DR4X4;1540591; said:
my dads 93 6.2 truck has factory single exhaust on it.
Yes, but it still doesn't have a Y-pipe, does it? The 93s I've worked on (with 6.2 diesels) still had a separate 2 1/2" pipe on each exhaust manifold - but they join at the muffler with the two pipes going in, and only one coming out - thus being single 3" exhaust from the mufffler back.

Same year with the turbo 6.5 used a single 2 3/4" exhaust all the way.
 

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If I recall correctly my 93 had a single 3" pipe into the muffler, with a y pipe. After the muffler mine had 2 smaller tail pipes, both on the passenger side, 1 about an inch or 2 behind the other. I don't know if that was common or not, but it was from the factory like that.
 

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Discussion Starter · #12 ·
When I lived in Connecticut there was a guy who built an entire exhaust system for his truck using 3" metal electrical conduit purchased at Home Depot and a hydraulic pipe bender he bought from Harbor Freight. I have know idea what he used for a muffler.

Does anyone have any experience with this method?
 

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76chevyc10;1542768; said:
When I lived in Connecticut there was a guy who built an entire exhaust system for his truck using 3" metal electrical conduit purchased at Home Depot and a hydraulic pipe bender he bought from Harbor Freight. I have know idea what he used for a muffler.

Does anyone have any experience with this method?
Not with conduit. I've been making my own exhaust systems with stainless-steel straight pipe I buy from J.C. Whitney along with a Harbor Freight pipe-bender. But, you cannot make very sharp bends or it buckles. For the sharp bends I buy the pre-bent stainless pieces - they come in 45s or 90s. I also use Dynomax straight-through stainless steel mufflers - 2 1/2". For tail-pipes - from the mufflers back - I use the J.C. Whitney "marine-grade" stainless-steel flex pipe. First system I made was in 1995 on my 83 diesel Blazer. Not a sign of rust on any of it yet - and I live in a rustbelt and it's used as a snow-plow truck. I was suspicious of the flex-pipe at first, but it's been great. Expensive though for the good marine-grade stainless.
 

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jdemaris;1540202; said:
The single exhaust would work fine as long as you had a low-restriction muffler. But, where would you get a stock Y-pipe from?
The exhaust outlets on small block chevy exhaust manifolds and the 6.2L exhaust manifolds used in '82-'87 trucks are in exactly the same location. I changed my '85 C20 from a 305 to a 6.2L, the old gas y-pipe matched up perfectly.

I have since switched from the stock single exhaust, to dual 2.5" exhaust with Dynomax super-turbo mufflers. I gained an easy 2-3 MPG. It feels peppier too.
 

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LDPosse;1582428; said:
The exhaust outlets on small block chevy exhaust manifolds and the 6.2L exhaust manifolds used in '82-'87 trucks are in exactly the same location. I changed my '85 C20 from a 305 to a 6.2L, the old gas y-pipe matched up perfectly.

I have since switched from the stock single exhaust, to dual 2.5" exhaust with Dynomax super-turbo mufflers. I gained an easy 2-3 MPG. It feels peppier too.
That's good to know - I wonder if GM intentionally designed things that way - or it's just coincidence? I've got a 79 K5 Blazer with a 305 gasser I'm going to drop a 6.2 in, sometime - but as of yet - never tried to bolt a 305 Y-pipe up to a 6.2 diesel.
I use the 2.5" Dynomax Ultraflow mufflers on all my diesels - they are the 1100 CFM stainless-steel versions. They cost a fortune but last forever. Last set I bought - they were $130 apiece - now they are up to $180 each.
 
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