Since nobody has taken the liberty to put together a thread on the slant six exhaust and a place for people to give their input from what they have done to their exhaust and what they like and dislike about it, i figured id start one since lately it has become a common topic. My goal is to have a thread with much input from fellow slanters that has opinions, questions and videos of different setups so that we have somewhere to link to when the topc comes up. This way we arent telling people to search it and have them come up with tons of results that they have to read through, which can be rather intimidating.

Ill give my opinion on different ways ive done my exhaust and ill try and post some pictures and videos of each setup ive done, which is too many

Stock Manifold Exhaust:
Ive done many setups with the stock manifold.
1. After passing DEQ when i got the truck i cut the tailpipe off. It added a little bit of sound but it also added drone, which in an old truck with no insulation is rather annoying.
2. I cut the muffler out and half way gutted the original clogged up cat, a little more noise a little more drone.
3.Redid my exhaust and put a 2.5" system on from the manifold back with new cat and a flowtech redhot glasspack with a turndown. Louder than #2 but a lot more drone since i had made my own cut out that leaked a bit. I drove around for quite some time with this setup about half a year with it i switched to a flowtech raptor turbo muffler which further quieted it but still droned.

My take on turndowns, theyre great for a drag car or weekend cruiser, but on a DD. They really suck! unless you have lots of insulation it is going to drone no matter where it exits under the car. If it exits under the car and isnt pointed out from under it with the tip at least 4" away from the edge of the sheet metal, it will probably drone. I say 4" because my current tip is about 3" away from the edge and it doesnt drone.

Dual Exhaust:
I got a set of dutra duals and i love them. With my old tired engine they really woke it up! They look great and i still get the heat riser function which will really be nice when it gets colder!

It seems like a lot of the people i see asking about running duals want to run true duals with an x pipe or H pipe. Well like most of the more knowledgeable guys on the board will say, a good flowing 2 into 1 exhaust will be much better and save weight. What i did with my dutras is I ran 2" pipe off the manifolds into a Y that goes into a 2.5" exhaust through a cutout then into a cat a glasspack and my raptor turbo muffler, a 4' tailpipe with turndown angled out in front of the rear passenger tire. There is no drone, I have a nice quiet idle, under normal cruise around town (under 2k) it has a nice mellow deep tone that sounds great. On the upper end (3k+) has a slight slant six rasp but not too bad. Its louder than a modern car but doesnt drone and sounds good. With my cutout open i get the full slant six split manifold sound, which might i say is awesome! 1 bolt i pull the cap off and it goes from a nice purr to the swarm of bees Nice kinda deep idle, very throaty under 2k, between 2-3k it transitions from throaty like a v8 to raspy, kinda like those old jag inline 6's and over 3k you get that slant six swarm of bees sound which sounds like a really big swarm But since my cutout exits under the passenger floorboard you can believe it drones like crazy when its open

Overall I preffer the dutras over headers, they were a little hard to plumb with a low mounted starter but they just sound cool and im not worried at all about them rusting like headers would, eventhough they dont use road salt in Oregon. n top of sounding cool my truck has gained signicant performance even with the stock 1bbl. I can now accelerate up hills and i have way more power in the upper end to pass on the freeway and can cruise at 65mph with very little throttle, in fact i get about 16-18 in/hg on my vacuum gauge at 65mph going down a flat freeway and can still keep over 10 in/hg while passing. Before those numbers were 12 in/hg and 5 in/hg respectively. With no other modifications.

I know i said in the beggining that i have done too many variations, but only listed a few. I have done much tinkering whith my exhaust, clamping pipes together to see what sounds good and what doesnt. Its late and ive had a long day. If anyone has any questions feel free to ask. If i dont have an answer for you, im pretty sure that there will be someone who can answer it for you. I will post pictures and videos (bare in mind most are cell phone videos so not the best sound quality) soon. I will try and take a video of my new exhaust with our good camera when i get the chance.

Hope this helps a lot of you,
Cody

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Old truck: 82 D150 225, 2bbl, dutra duals, 2.5" straight pipe to dual 2.5" tail pipes. Mud tires, 4spd, old forest service truck.
Current truck: 98.5 Ram 2500 ccsb, sport, 24v cummins, 5spd, 4.5" lift, 35's, 5" straight pipe.

Here is what I have run on my truck for years but is about to change when I put the Dutras on it.

2 1/4 head pipe back into a thrush turbo muffler, and from there it goes into the stock 2" tailpipe and out the back. No drone, sounds like stock (wimpy). I plan on running two 2" pipes into a Y pipe and swapping out the existing muffler with a junkyard flowmaster I picked up for $20.

On my Duster I ran a 2 1/4 pipe into a flowmaster 40 with a 2" exiting out to the rear in the stock location. Very quiet actually and could barely be heard in the car going down the road. But the 2.76 gears and low cruise RPM had a lot to do with that.

I ran my Dakota (3.9 V6) without a tailpipe for a week to see what it sounded like (flowmaster 40). That had to be the most annoying sound EVER. The slightest touch of the throttle created a drone so loud that it rattled everything inside the truck. At full throttle it sounded like a 6-71 Detroit in a firetruck (which was cool as hell). I also lost all of my low end torque with the tailpipe gone.

I put the tailpipe back on it and cruising down the road the exhaust is barely audible. Under acceleration it's very audible but far from loud. I really didn't need to change the pipe sizes any since the Dakota comes with a very free flowing exhaust system with large pipes.

That's my .02 on six banger exhausts. As you can tell I like my exhaust to be loud, but a lot of people don't. But as far as pipe sizes go 2 1/4 from the manifold to the muffler and 2" from there back is good for 90% of the slants out there still running a stock manifold.

The Dutra's are really worth the money, and in my opinion should be one of the first performance upgrades done to a slant.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

Except for this one.

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Thanks Zorg! i hadnt seen that one.

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Old truck: 82 D150 225, 2bbl, dutra duals, 2.5" straight pipe to dual 2.5" tail pipes. Mud tires, 4spd, old forest service truck.
Current truck: 98.5 Ram 2500 ccsb, sport, 24v cummins, 5spd, 4.5" lift, 35's, 5" straight pipe.