Accurate Exhaust

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bighammer

bighammer

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I was looking at their website shopping for a set of head pipes. They claim they make them to factory specs. I called the company because I thought I saw a typo...

I have The 340 HP manifolds with the 2 1/4 outlets. So I obviously thought the head pipes would be 2 1/4 inch. The guy on the phone says the head pipes are two inch, and that they increase to 2 1/4 after they get down below the engine compartment.

Is that really how Mopar did them? Makes no sense to me to neck them down like that. What size did the 1970 340 Dart use? I'm working on getting my 360 ready for the swap.

Thanks
 
......................Accurate is correct for 1971 and later........68 -70 the drivers side was 2 inch for about the 1st 2 feet.............pass side was 2 1/4 rite off the manifold...........kim.........
 
oldkimmer said:
......................Accurate is correct for 1971 and later........68 -70 the drivers side was 2 inch for about the 1st 2 feet.............pass side was 2 1/4 rite off the manifold...........kim.........
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Oldkimmer is dead on. With the 49-53 casting exhaust manifolds (68-70), the left head pipe up front was 2" O.D. and increased to 2.25" at the intermediate pipe. But we do make a custom head pipe that has a 2.25" flange pipe for automatic equipped applications.The right side has a 2.25" flange pipe and this is how our head pipes are manufactured as well.
71-74 is different as mentioned by oldkimmer. The right side 623 casting is a ball joint(no gasket) style connection and requires a 2" flange pipe.
 
Thanks for the replies, Oldkimmer and Tom. Tom, the manifolds I have for my car may not (?) be a matched set, but they both have 2 1/4" outlets, and neither side has a ball flange. From what you posted above, it sounds like I can get 2.25" all the way thru?

Thanks
 
check out the stocker
 

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I scrapped my compression bent 2 1/4" Accurate system for the mandrell bent 2 1/2" system by TTi. If you're concerned with following the OE pipe route, then stay away from the TTi system. Their driver side head pipe goes straight back from the manifold and totally avoids snaking around the torsion bar/starter/steering box.

I don't have a pic of the head pipes, but this shot of the tailpipes will give you an idea of the difference. Plus I picked up almost three tenths at the track with the TTi pipes over the Accurate pipes.

tailpipes.jpg
 
I'm right at picking the exhaust from the manifolds back also. Putting a 360 in my 69 cuda. Any chance you could post some pics of fitment for the head pipes? Particulary concerned with starter/torsionbar area. Thanks
 
Only other pic I have of the new TTi system. For the street, the Accurate system was just fine. Mine was 12 years old when I removed it. It was in such good shape (you can tell by looking at the condition of the old tailpipes in the other photo) that I gave it to a buddy of mine to replace his OE pipes on his 340 Swinger. I ~think~ the cost of both systems is about the same.

Xpipe.jpg
 
Thanks for posting the pics! I can see the difference in the quality of the bends. If your gonna put on an exhaust why not gain three tenths? BTW your ride looks as great as it runs.
 
ir3333 said:
...was that 3 tenths of an increase on a stock 275 hp 340?
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Yes it was. I run in the Pure Stock Muscle Car Drag Races so it HAS to be stock. We get to run any rear gear ratio, and we can upgrade the stock exhaust to a max of 2 1/2" with H and X pipes allowed. Mufflers have to be oval if so equipped from the factory, so I run DynoMax Ultra Flo mufflers.
 
69conv said:
I'm right at picking the exhaust from the manifolds back also. Putting a 360 in my 69 cuda. Any chance you could post some pics of fitment for the head pipes? Particulary concerned with starter/torsionbar area. Thanks
Click to expand...

If you go to this link http://www.accurateltd.com/A-Body-Headpipe-Tech_ep_34.html there are some pictures of how our left 340 head pipe is designed to clear the starter , pitman arm and torsion bar without indenting the pipe.
This makes for a better flow and still maintaining the O.E. configuration.
 
I wish there was a better way to run stock manifolds and not have to use the 90* adapter on the pass side. I'm doing it with a shorty filter, but have to remove the headpipe to change oil filters.
 
bobscuda67 said:
I wish there was a better way to run stock manifolds and not have to use the 90* adapter on the pass side. I'm doing it with a shorty filter, but have to remove the headpipe to change oil filters.
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You need your 90* adapter clocked in the correct position. Im running stock (1968, 340) manifolds, TTI 2.5" head pipes, and the full size filter.

Now it's not the easiest filter in the world to change but I don't need to take anything apart.
 

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1968FormulaS340 said:
You need your 90* adapter clocked in the correct position. Im running stock (1968, 340) manifolds, TTI 2.5" head pipes, and the full size filter.

Now it's not the easiest filter in the world to change but I don't need to take anything apart.
Click to expand...

Yep, I had an adapter and it would leak, even after I changed the gaskets.
 
bobscuda67 said:
Yep, I had an adapter and it would leak, even after I changed the gaskets.
Click to expand...

The base gasket that you get with the M/P kit is too thin. The bolt was bottoming out without squeezing the gasket. Mancini has a THICKER base gasket (that they used to supply automatically if you bought the 90* M/P lit). I have used that thicker base gasket and have never had a problem with leaking.
 
GTS Registry said:
The base gasket that you get with the M/P kit is too thin. The bolt was bottoming out without squeezing the gasket. Mancini has a THICKER base gasket (that they used to supply automatically if you bought the 90* M/P lit). I have used that thicker base gasket and have never had a problem with leaking.
Click to expand...

That explains it!
 
bighammer said:
Thanks for the replies, Oldkimmer and Tom. Tom, the manifolds I have for my car may not (?) be a matched set, but they both have 2 1/4" outlets, and neither side has a ball flange. From what you posted above, it sounds like I can get 2.25" all the way thru?

Thanks
Click to expand...

Yes you can get a full 2.25" system. But you will need to beware that unless you use a full length 3 tube , 3 baffle reverse flow muffler you may experience some unwanted passenger compartment resonation under load and acceleration. Our tubing is of a heavy gauge material which will alleviate some of the resonation with high flow style mufflers but it will not alleviate it enough for some. We are careful to be on the conservative side of what mufflers we supply for a customer so as not to have a drone/resonation problem and even then we still get some. Chrysler engineers were pretty sharp on exhaust technology back in the day.They started bigger up front and tapered down the exhaust at the rear. This kept the exhaust pulse stronger through low and mid range rpm which is where most of us drive anyways. The bigger the pipe the more rpm it takes to keep the exhaust pulse waves strong especially aft (rear) of the mufflers. That is why it may be of no benefit to increase the left head pipe size at the flange from 2" to 2.25" for your application. Only if you are consistently running at 4-6k rpms would bigger pipe be of any real value.
 
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