Ulfhedinn
Registered Member
Im thinking of changing out the exhaust on my M1009. Any recomendations?
CK5
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6.2L Diesel Exhaust upgrade?
- Thread starter Ulfhedinn
- Start date
2.5" duals with Flowmaster 40's. You'll gain some power, and it'll at least sound like a big block. 
There really isn't any way you can go too big on diesel exhaust, it doesn't need the backpressure at all. However, the outlet size on the manifolds is just shy of 2.5", so there isn't much point going bigger than that.
Rene
There really isn't any way you can go too big on diesel exhaust, it doesn't need the backpressure at all. However, the outlet size on the manifolds is just shy of 2.5", so there isn't much point going bigger than that.
Rene
gt1009
1/2 ton status
I did the ghetto mod and ran dual cherry bomb glasspacks on mine. It sounded pretty good, but loud. I feel like I gained a little power but nothing really worth noticing.
super k
1/2 ton status
I went with custom 3" duals and the 6" round Magnaflows. I noticed a pretty good increase in power
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I cobbed two thrush glasspacks onto my '82 K2500 just to pass inspection when the stock duals rotted off it...they sound nice,like a small block with them does--might have given a slight HP boost--but I used pipes I had lying around that were supposed to be chain link fence pipes,thick & galvanized,so I used them to save $$$$$....one is a bit smaller than 2" I.D,the other is 2-1/8 I.D.....I know the backpressure is probably a bit more than stock now,but I swear it has a little more snot at low rpms than it did with the regular mufflers & pipes..maybe its just because it sounds meaner,I dont know...I put them on a year ago and barely drove it,the mufflers still look new,so does rthe pipes..
Cornfield creations
1/2 ton status
2.5" duals with Flowmaster 40's. You'll gain some power, and it'll at least sound like a big block.
There really isn't any way you can go too big on diesel exhaust, it doesn't need the backpressure at all. However, the outlet size on the manifolds is just shy of 2.5", so there isn't much point going bigger than that.
Rene
The stock manifolds, have 2.5" outlets? Do they have the same bolt pattern as a regular small block to bolt up?
I think they're a little bigger than 2.25" actually. I've read they can be opened up to 2.5", but it gets a little tight to the studs.
Rene
Rene
shovelbill80
1/2 ton status
i'm 99% sure the 6.2 and smallblock manifolds end at the same exact spot, so i don't see why you couldn't use any exhaust that would fit......someone will let me know about the other 1% though 
I got a stock "Y" pipe for the gassers, fits an 89 model. Brand new!
I'll let it go for a Benjamin!
I'll let it go for a Benjamin!
You are correct. Any exhaust that would bolt up to the exhaust manifolds on a K5 with a gasser would bolt up to the 6.2L's manifolds.i'm 99% sure the 6.2 and smallblock manifolds end at the same exact spot, so i don't see why you couldn't use any exhaust that would fit......someone will let me know about the other 1% though
Cornfield, no, the 6.2L manifolds will not bolt to a SBC.
I think I've decided to just stick with duals on mine. Going to a 3" single would just be a decent amount more work and expense when I can buy the Thrush/Hedman 2.25" mandrel bent setup for less than $250 total.
Still having no luck finding an exhaust shop around here that does true custom work and doesn't immediately make me fear handing them the keys to The Blazer. If I can find one I might go with a dual 2.5" setup like tRustyK5 described. Maybe some quieter, better flowing mufflers though. Not sure.
Using the stock setup the pipes are actually smaller than 2.25" at the manifolds in order to clear the stock retention method. Just look at the stock pipes that are 2.25" and you can clearly see where the diameter is reduced right at the manifolds. The actual manifold outlet is right at 2.5" but you have to make an adaptor to get a 2.5" pipe to bolt up without any reduction in size.
