1975 IH 150 pickall dual exhaust in the way for 727 install

[Rusty Scout]

And other questions.

The pipes are sound and heavy. I was thinking to myself as that tranny was coming out ya know it probably would have been a good idea to remove the exhaust and front drive shaft. Going back in soon and I am fighting that exhaust. The po put some big ol glass packs in there and welded these pipes into one long piece.

Questions

I was fixin on cutting the pipes somewhere before the mufflers and the getting some of those no weld stainless butt splice clamps for the 2.25 pipe. Another po virus or do theses clamps work well?



Or keep em one piece and just move aft as far as possible for integrity?

Also the pipes on the engine side of the glass packs are 2.25 but aft seem a bit smaller. What should those tailpipe diameters be?

 

[Eric VanBuren]

Now you know why tranny guys heat exhaust guys.

Yes those clamps work well but they are not for a butt splice, they are intended for a piped slipped in another pipe. If you take a closer look at the pic you'll that they are stepped.

If the mufflers are to the back of the truck using one size smaller tail pipe will actually help low end torque. The exhaust cools and contracts as it makes it's way to the back so there is less volume. Making the tail pipe a bit smaller keeps the velocity constant and helps with a slight scavenging effect at the low end. The trade off of course is that it May restrict the top end hp slightly.

 

[Rusty Scout]

Copy that. It seems that they are making butt joint ones as well as the lap joint type that you mention. They are in the exhaust clamp section of summit.

The only thing I do know is if I had the ability to remove the head pipe without trying to pull the whole exhaust over the rear axle on jack stands on an uneven asphalt driveway life would be a whole lot easier.

 

[Michael Mayben]

Having just fabbed a fresh exhaust rig on my similar truck steve, I would not even screw with what you have on it right now. Clamp-on stuff like that is for folks who are graduating from using beer cans and radiator hose clamps for exhaust pipe patches...or sailor jerry!

Once it's a driver again, I'd bite the bullet and take the ride to an exhaust shop and have them do the cut/splice/whatever.

I went the diy route simply because I have an excellent supply of bends, nipples, reducers, tubing, etc. Sitting on the shelf at the parts house I can scrounge through. Took me hours to select all the parts for each side, then hours more to cut and paste with the mig. And nothing will have to be removed if the engine, driveshafts, tranny, or transfer case ever need to be removed.

Most folks aren't so fortunate to have the parts supply I have, nor the free time to do this stuff! Right in the middle of welding up the second set of exhaust runs, I ran out of steel mix for the mig and had to convert back to flux core. So the weld job looks like shit but then I don't drive around upside down looking at the exhaust system like Robert does on his roadster!

 

[RobertC]

From a historical / stock / oem point of view (full size / from "memory"):

the original mufflers (oval) were 2 1/2 in. In / 2 1/4 in. Out

the pipes were "sized up" entering / "sized down" exiting the muffler "immediately" / within a couple inches.

The pipe to the muffler is 2 1/4 / tailpipe is 2 in (I believe) the tail pipes have been replaced once on my t/a.

The original driver's side pipe from the manifold to the muffler had 3 / 4 bends in it -- my assumption was that it was to "go around" the 727.

I always had problems with exhaust coming loose, so I had the "rube goldberg" edition replaced with a "straight" pipe.

The mufflers were hung behind the center bearing cross member from 2 brackets (on each side if you have factory duals).

Here is a picture of an original muffler hanger:

 

[Eric VanBuren]

My mistake, I didn't realize that summit offered ones intended for use with 2 pipes of the same size. I've only used the ones like in the picture. I wouldn't trust the butt splice ones though unless they are much thicker than the normal ones. In regards to that style of clamp in general they are far and away the best way to connect two exhaust pipes. They are the only thing used on modern md and hd trucks. It makes for much easier servicing. I can change a muffler on a "thousand series" International truck in about 15 minutes. Since those clamps don't distort the pipe once they are removed the pipes slide apart very easily.



If the exhaust is solid and you're happy with it then I'd slice it nice and square in a easily accessible location. Then once you have the truck up and running temporarily splice it back together with a couple of tin cans and hose clamps for a trip to the exhaust shop. Then you have 2 options 1. Have them weld the pipes back together or 2. Have them install some flanges so you can take it apart easily later to access things if need be. I'd have them use either common header style flanges or ones used on popular GM catalytic converters so that you know you can easily get replacement gaskets.