Folks, Lou and Sandy in BC,
In the interest of creating a record of exhaust systems that REALLY achieve a deep V8 sound on trucks I want to report on what following forum advice got me for my '64 d100 pickup with Dutras and extensive engine building and 4 speed. As the alignment shop guy said, "I thought it had a 440 in it so I took it up the street to get on it!"

What I got is custom made exhuaust system that turns heads on the street for its deep V8 sound, no resonance on acceleration or on cruising, seems located to maximize low end torque and looks as if it has what Sandy in BC (July 17) called "the tuned length". Sandy said: "The "tuned length" is going to be 32" to about 38". On Chev 250 6's with factory split manifold (about 80-82) the primary length is 32.5". Lou (Dart 270) is saying 36" (I think this is based on Cameron Tilley research). ...Knowing this I would put the Y somewhere in this range based on convienience and pricing.

Because the manifold is a log type and the runners are not equal length Vizard might suggest making the Y where the short runner and primary length is close to 32" and the long runner is close to 38" . That way you increase your torque band by always having some cylinders close to optimum.

But...then again...I could be full of shyte...."

Well Sandy, there is no s... in you or Lou! I went to R&J and entire system hand made with stainless pipe cost $380 including a beautiful stainless tip on the pipe end. The muffler is a Flo Pro FP212. This is surely a heavy duty muffler and appears hand welded together. This is not a stamped together can and endpiece deal. Custom welded Y, not a Flowmaster. Primary runner from the front Dutra is 35 inches of 2 inch pipe to the input of the Y; the secondary runner from the back 3 cylinders is 2 inch pipe running 28 inches to the input of the Y. The muffler is 14" x 10" x 4" and has a 2.5 inch exit. The pipe runs 58 inches to the back axle from the rear of the muffler, then the pipe arches over the axle and exits on driver side. The muffler is located just below where the cab and bed meet and extends rearward past that point. I had to locate it here because of the room being taken up forward by the A833OD linkage, Wilwood slave and cross member I had to make while leaving in the original cross member.

I realize this system is longer than a car exhaust (or I reckon it is) but the up front stuff may help one of you car guys see how a really rich sounding slant can be fitted in with Dutras and still squeezed past the dipstick and Andy F's low hung GM SI 12 alternator on driver side tha I switched in.

regards to all,
rock
'64d100

Great writeup. Any chance you can record some sounds for us?

How long is your muffler?

And, on a scale of 1 to 10, 1 being "stock silent" and 10 being "no muffler at all", how loud would you say your system is as heard from outside the truck?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Glad you found what you were looking for! I've finally decided that my Dutra Duals with 2" pipe back to two Borla Pro XS mufflers and out the rear sounds like... (I'm ready for the outrage!) a cross between a Ricer and a Semi truck! Now I just need a pair of 6" dia. chrome tips...

I guess it stands to reason, since most semi tractors use (albeit large) inline sixes. I'm sure an h-pipe would quiet it down some, but since I'm hoping to make the T-5 conversion someday, I'd rather the exhaust didn't get in the way any more than it already will (and I can't afford to have five flanges installed — that will have to wait on my next, better quality exhaust system).

Like the old codgers said, the volume gets a little old once moving, but it sure sounds nice at idle...

VM

Well Im glad that worked out! You should stop by on the weekend so I can hear it in person.

How was R&J with the science you brought them? ....did they have any comments?

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Yeah....Im the one who destroyed this rare, vintage automobile.....

Thanks a lot , guys!
Dan your nice comment is really appreciated, cause as you know your help got me to this point! The muffler is 14 inches long (18 from pipe in and outs) and 10 inches wide by 4 high...its a big un. I can record the sound and think I will give it a whirl. After recording it I don't know what to do to make it available, but might just mail you a CD..

Vynn, it seems the Flo Pros are stock in trade for semi trucks so your comment re. you being a cross between a ricer and semi are interesting...but mine is not raspy at all and gets quieter the faster you go...very mellow indeed. My tip is a 5 inch tip! I was going to use a chrome stack through the truck bed but that got into poly dollars (like $300 more) and that was too cool for my blood.

Sandy, I would love to "run up" to BC! I have this notion from Discovery Channel that BC would be a very nice place to live and see! And I have had a great time every time I have been in Canada...love the folks. The muffler wizards at R&J agreed with the "science" of tunable exhausts and in fact were familiar with it. They had not had many people other than Lou ever talk to them about it, though and enjoyed the chance to show some of their knowledge. There are computer programs (based on empirical info I bet) that manipulate exhaust velocity, volume and density, temp, pipe diam and material and header lengths to predict sound. Not unexpected in a shop with a block long length of bays with the giant quarry trucks on one end and volkswagens on the other...this place is "expert"!
rock
'64d100