Precision Street Rods & Machines - Building Quality Cars Since 1982
Precision Street Rods & Machines
"How We Make Exhaust Headers & Tail Pipes"
 
 
 
The car that we will be working on today is “Hot-Rod” Dorman’s 1940 Ford convertible. It’s sporting a 400ci. Olds. mill. Rod is more interested in the performance and looks of his exhaust system than he was in using a stock set of manifolds and building around them. With this in mind, we set out to make our own headers and tail pipes using U-bends.
 
A U-bend system offers you an unrestricted (no kinks in the bends) free flowing exhaust system. It also allows you to have a more tailored / tight system as you don’t need to have any straight pipe between the bends (a little more than twice the diameter of the pipe is needed for the tube bender dies). You can also have a twisting bend as well. This is impossible to obtain any other way.         
 
FYI: Exhaust headers don’t have to have equal length tubes for a street or slightly warmed over engine. Also, the longer and or smaller the I.D. of the pipes are, the better the torque curve will be. The shorter and or larger  the I.D. of the pipes are is mainly for horse power. This holds true for the tail pipes as well.
 
Follow along as we show you how we went about making Rod Dorman's trick exhaust system.
 
 
INSTRUCTIONS: Roll your mouse over the the photo, left side click to view it in a larger format. Use the manual arrow buttons to proceed in either direction. Use the (X) button to return to the original format.
 
OPTION: Click on the bottom left arrow to start the automatic slide show in the larger format, Click it again to pause the show.
 
 
 
Phoro 1
Phoro 1
(Finished)
Photo 2
Photo 2
Photo 2: These are the parts that we will be using to build our headers. Notice that there are two different size radiuses’s on the 1¾ inch u-bends and the collectors are long enough so they can be trimmed to size.
Photo 3
Photo 3
Photo 3: This is how the project started. Since the car has air ride suspension, we released the air in the system to give us the tightest working area. This assures us that nothing will hit during the cars suspension travel. Next we turned the wheels inward at the rear for the same reasons.
Photo 4
Photo 4
Photo 4: To get things started off, we bolted the head flanges in place. Notice how thick they are, a full 3/8 of an inch thick.
Photo 5
Photo 5
Photo 5: Rod Dorman;s car is based around a Wescott fiberglass ’40 Ford body. Wescott uses a pair of bolt-on metal body braces to connect the firewall to the frame.
Photo 6
Photo 6
Photo 6: After we unbolted the braces from the firewall, we bolted them to the frame in the appropriate places. This was to obtain our working area boundaries.
Photo 7
Photo 7
Photo 7: We placed the collectors in the approximate area we wanted them to end up
Photo 8
Photo 8
Photo 8: We found that the easiest way to get an idea as to how our pipes will look is to use some pre-heater hose (the hose that connects the air cleaner tube to the top of the exhaust manifold on most smog controlled cars / trucks) as a template. This hose is easily bent and will retain its shape.
Photo 9
Photo 9
Photo 9: Simply put, we bent the hose until we were happy with its new shape. We started with the #5 cylinder, and then checked it against the #3 cylinder, as they will be siamesed together.
Photo 10
Photo 10
Photo 10: As you can see, this hose is a larger diameter than the actual tubing that we will be using. That’s why we used it to get us started only.
Photo 11
Photo 11
Photo 11 & 12: After we welded, ground and polished our welds, we tack welded the tube to the collector and head flange. This gives us a good foundation to start from. If you choose to remove your seams as we did, beware that the tubing is thinner in the bends and your match has to be exact.
Photo 12
Photo 12
Photo 13
Photo 13
Photo 13: Notice that we had to turn our round tubing into a rectangle in order to match our port openings.
Photo 14
Photo 14
Photo 14: We bolted the first header tube in place to see if we were on the right track. We were happy, so we will move onto the #3 cylinder next.
Photo 15
Photo 15
Photo 15: We won’t be using the pre-heater hose anymore. Instead, we will be using the actual u-bend tubing. We will be using sections of the u-bends to get our initial shape. Be aware that there are to different radiuses to choose from. We used the larger of the two for the #3 cylinder.
Photo 16
Photo 16
Photo 16: Here you can see us marking the corners of the rectangular shaped flange onto the round tubing. This is the first step in the transformation process from a round shape to that of a rectangle.
Photo 17
Photo 17
Photo 17: Gently, we used a torch and hammer to start the re-shaping process, primarily concentrating on the sides. Our rectangular shape is taller than it is wide. All we want to do at this point is to get it in the hole. We will deal with finalizing the shape once it is in the hole.
Photo 18
Photo 18
Photo 18: We centered the tubing in the hole and tacked it in place. The tacks should go on the sides so that you can still move the tubing around.
Photo 19
Photo 19
Photo 19 & 20: Again we heated the tubing to an orange color, and then we proceeded to reshape the tubing by using a round punch in the corners.
Photo 20
Photo 20
Photo 21
Photo 21
Photo 21: Now that we got the flange side fitting, we can concentrate on the collector end. Just as before, we will be using a u-bend section to make pipe from. For this application we used a small radius bend as it is an inside bend.
Photo 22
Photo 22
Photo 22: This is how the pipe looked after we cut it out of the u-bend. We had to add a tiny piece of straight pipe to the bent end in order for it to fit all the way into the collector.
Photo 23
Photo 23
Photo 23: When we slipped the pipe into the collector, we noticed that we fell short of joining the two sections together by 11/2 inches. We will have to add a piece of straight pipe here. Make sure that your cuts are square, otherwise you will either be filling a gap or even worse, your pipe will take on a bend.
Photo 24
Photo 24
Photo 24: If you look closely, you’ll see the section that we added to one half. Now all we have to do is to join everything together.
Photo 25
Photo 25
Photo 25: All of the welds were removed at this point and the pipe is ready to install. Again, tack weld the pipe to the collector and flange only.
Photo 26
Photo 26
Photo 26: Now that we have the two middle cylinders finished, we can concentrate on finishing the #1 cylinder.
Photo 27
Photo 27
Photo 27: We placed a pair of the large radius u-bends in the remaining collector holes. They will be used for our #1 & #7 cylinders. As before, we used the larger radius when the pipes will be running on the outside of an existing pipe.
Photo 28
Photo 28
Photo 28: The #1 cylinder is the next port that we will be working on. It will be running over the top of the #3 pipe. At this point we opted to use the larger diameter u-bend out of the head flange. Not because we had to, we wanted a softer looking bend.
Photo 29
Photo 29
Photo 29: As you can see, one of the pipes will have to be trimmed. For no reason at all, we chose to trim the one at the collector.
Photo 30
Photo 30
Photo 30: If you look closely, you can see where we seamed the pipes together. The pipe will also be ground and polished smooth to match the rest.
Photo 31
Photo 31
Photo 31: Well we’re finished with the #1 cylinder. Now we get to make the last pipe. As before, we will follow the same type of prosecutors.
Photo 32
Photo 32
Photo 32 & 33: This is the trickiest pipe to make as it will be made up from several small pieces. Your cuts will have to be true and square to each other for this one to look right.
Photo 33
Photo 33
Photo 34
Photo 34
Photo 34: As before, we left the seams in for you to view. These too, will be polished to a smooth finish.
Photo 35
Photo 35
Photo 35: We can concentrate on finishing up the collector now. The first thing that we did was to mark where the pipes ant the collector met. We will need this line so that we know where we can safely trim our pipes the same length.
Photo 36
Photo 36
Photo 36: As you can see, all of our pipes are within our line. We will trim all of the pipes to the shortest length. This is pretty much an 1/8-inch inside of our line.
Photo 37
Photo 37
Photo 37: All of our pipes are trimmed to the same level. Ready for the next step.
Photo 38
Photo 38
Photo 38: If you don’t make a diamond shaped filler, you will have a major leak between the four pipes.
Photo 39
Photo 39
Photo 39: You will need to weld the edges of the pipes together as well for a leak proof system. We went al the way to the edges of where the pipes touched.
Photo 40
Photo 40
Photo 40: Lastly, you will need to rap all of the edges past your collector line.
Photo 41
Photo 41
Photo 41: We wanted a super tight fit between the pipes and the collector. To do this, we used a blunt chisel to move the metal a little closer to our rapped pipe welds.
Photo 42
Photo 42
Photo 42: If you look closely, you’ll see how tight we got the collector to fit. See the raped weld protruding past the collector edge. This will give us something to weld to. All that is left is to weld the collector in place.
Photo 43
Photo 43
Photo 43: After we welded the tubes to the head flange (from the inside), we used a die-grinder to grind our lumpy welds smooth, thus giving us a non restricted flow. Not a mandatory step.
Photo 44
Photo 44
Photo 44: We used a 3-inch disc grinder to smoothen any unwanted weld that protruded into the sealing surface of the flange. This surface has to be as flat and smooth as possible to insure a positive seal against the head.
Photo 45
Photo 45
Photo 45: Here is a sneak look at how our flange turned out.
Photo 46
Photo 46
Photo 46: All that is left is to bolt the header back on the engine and admire our efforts.
Photo 47
Photo 47
Photo's 47 & 48 Finished!. As you can see, there is plenty of room around the exhaust.
Photo 48
Photo 48
Finished!
Photo 49
Photo 49
Here is an overview of the parts that we will be using. It consists of everything that you will need from the mufflers to the 2 1/2" U-bends, the sections of straight pipe right down to the mounting hardware.
Photo 50
Photo 50
Photo 50 & 51: This is where we will be starting our project, the exhaust headers. We will be tapping into them through the side rather than the bottom. This is for additional ground clearance and the ability to un-cork the headers at the collectors without disconnecting the rest of the system.
Photo 51
Photo 51
Photo 52
Photo 52
Photo 52 & 53: As you can see, we have a confined area with few access holes to work with. We will need to enlarge and add holes in our x-members in order to run our exhaust through the frame rather than under it.
Photo 53
Photo 53
Photo 54
Photo 54
Photo 54: This is the existing hole in the x-members that we will be enlarging from 3 inches to 4 inches. There is one on each side of the frame. As you can see, we moved the hole opening off center
Photo 55
Photo 55
Photo 55: We chose to open the holes using a plasma cutter. You can use a cutting torch or die-grinder instead.
Photo 56
Photo 56
Photo 56: Here is a look at the piece that we removed from the x-member.
Photo 57
Photo 57
Photo 57: We cleaned up the rough edges with a die-grinder.
Photo 58
Photo 58
Photo 58; The x-member on the right has been modified, notice how much larger the access hole is. Now we can proceed with the left one.
Photo 59
Photo 59
Photo 59: We used a 4-inch hole saw to make all of the other access holes.
Photo 60
Photo 60
Photo 60: Here you can see how nicely that the 2½-inch exhaust pipe will pass through the 4-inch hole in the x-member.
Photo 61
Photo 61
Photo 61 & 62: Here is a general idea as to how we would like our exhaust to run. Nothing is welded yet.
Photo 62
Photo 62
Photo 63
Photo 63
Photo 63: We chose to flange our mufflers rather than clamp a slip fit. This way we can simply drop the mufflers straight down when it comes time to replace them instead of un-doing the system and prying the parts apart with the possibility of damage.
Photo 64
Photo 64
Photo 64 & 65: The first thing to get mounted is the mufflers. We used two pieces of ¾-inch angle iron to position our mufflers. They ran under the mufflers, between and on top of the lower 4-bars. We wired the mufflers to the angle iron, and the angle iron to the 4-bars to hold thing securely until our mounts are installed.
Photo 65
Photo 65
Photo 66
Photo 66
Photo 66 & 67: These are the parts that we used to make our mounts. A piece of 1 ½-inch u-channel cut on a bias, muffler grommets and washers, 3/8-inch nut & bolt,
and a piece of 1-inch by 1-inch u-channel.
Photo 67
Photo 67
Photo 68
Photo 68
Photo 68: This is where we decided to place our muffler brackets. They will be attaching to the inside of our 4-bar frame brackets, 1/2-inchs down from the top.
Photo 69
Photo 69
Photo 69 & 70: We leveled the brackets front to rear and side-to-side. When we were happy with their location, we tack welded them in place.
Photo 70
Photo 70
Photo 71
Photo 71
Photo 71: Next, we welded the other half of the muffler bracket to the muffler its self.
Photo 72
Photo 72
Photo 72: Now that the mufflers are stationary, we can proceed with our project. We will build the forward sections next. We built both sides simultaneously for a mirror image.
Photo 73
Photo 73
Photo 73: Because of the tight quarters of the driver’s side, it will be easier to copy if we do it first.
Photo 74
Photo 74
Photo 74 & 75: In order to not have our pipe hang so low, we will need to notch the break pedal bracket a little bit. We gained a full 1 1/4-inch of ground clearance by doing this
Photo 75
Photo 75
Photo 76
Photo 76
Photo 76: We used a 2 ½-inch hole saw to drill a hole for our side collector. The bottom of the main collector will be blocked off completely with a bolt on solid plate.
Photo 77
Photo 77
Photo 77: These are the parts that will make up the side collector. It is 3-inches long.
Photo 78
Photo 78
Photo 78: Here is what the side collector looked like when the pieces were put together.
Photo 79
Photo 79
Photo 79, 80 & 81: We placed the side collector extension into the main collector. We used a marker to outline the trim line (the part that protrudes into the main collector).
Photo 80
Photo 80
Photo 81
Photo 81
Photo 82
Photo 82
Photo 82: We removed the excess material with tin snips.
Photo 83
Photo 83
Photo 83: As you can see, the pieces will fit like a glove with no inside obstructions.
Photo 84
Photo 84
Photo 84: The pieces fit like a glove. We welded the two together and ground the welds smooth. All that is left is to install the bottom 3-hole flange for the block-off plate. This style of header is called a 4-tube dump style header or fender well header
Photo 85
Photo 85
Photo 85: Now that our header is finished, we can re-install it and copy the same steps for the other side.
Photo 86
Photo 86
Photo 86: Now we have a starting point and a finishing point, we can concentrate on connecting them together. This is how the u-bend pieces were made up to join them together. This piece is a little long at this point. We will trim it to size later.
Photo 87
Photo 87
Photo 87 & 88: The next thing on the agenda is to mark our final trim size and weld the pipes together.
Photo 88
Photo 88
Photo 89
Photo 89
Photo 89: Here is how our finished pipe looks; all that is left is to copy it for the other side
Photo 90
Photo 90
Photo 90: This is how the Drivers side pipe looked after it was installed. We have no less than ½-inch clearance at any one point.
Photo 91
Photo 91
Photo 91: We will short cut to the finished tail pipe next. We made it the same way as we made the front pipes, from many u-bend pieces joined together.
Photo 92
Photo 92
Photo 92: The almost finished pipe on the left shows how we went over the rear-end housing. The one on the right shows the pieces that it took to make it happen.
Photo 93
Photo 93
Photo 93: We made part of our rear muffler hangers from pieces of a 3-hole flange. This part will be welded to the pipes.
Photo 94
Photo 94
Photo 94: These are the rest of the pieces that we will be using to hang our tail pipes. A 3/8-inch nut and bolt, two rubber grommets, washers and a muffler strap bent 90 degrees at one end.
Photo 95
Photo 95
Photo 95 & 96: This is where and how we installed the tail pipe hangers. This type of mount works best when the bolts are vertical. This way you are compressing the full grommet and there is no chance of the grommet sliding out of the hole it is supposed to fit in.
Photo 96
Photo 96
Photo 97
Photo 97
Finished!
Photo 98
Photo 98
Finished!
 
 
 
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