FE Header Assembly Order

[Seymour Snerd]

The first few times I assembled GT40 Mk II headers to the FE engine in my SPF GT40 I struggled quite a bit, scratched up their ceramic coating, and then immediately forgot whatever it was I learned in the apparently random walk I took in determining the assembly order. Being 2-1/4" diameter there is very little clearance between the headers at multiple points so I suspect there is exactly one correct assembly order.



However, thanks to a comment by Adam Christian I just now successfully completed the operation without fuss, scratches, or procedural U-turns. Here it is in case anyone might find it useful. This procedure or some variant may also work with small-block headers, but I don't know. And they may be less difficult anyway given their smaller diameter.

1. It's significantly easier if the lower holes in the header flanges are slotted so the flange can be slid laterally onto the lower screw. My stock SPF headers are like that. I assume here we are using screws, not studs and nuts. Also, I am deliberately not referring to cylinder numbers, but rather will refer to the header positions relative to the each other, while facing forward.
2. Start all eight of the lower screws in their holes in the head. If you do not have slotted lower holes you will skip this step and start the lower screws after the first four headers are placed.
3. Put the four inner headers in place resting on the lower screws. Arrange their outlets to form a neat close square with their ends aligned. These headers form the two inner pairs of outlets and are the ones that do the crossing over which is why they have to be placed as a group. A bungee cord or large rubber band around all four outlets might help stabilize the assembly, although I did not find that necessary.
4. If you are using a Felspro gasket or any other that has slotted lower holes, you can now slide it into place from above.
5. Place the forward pair of headers in place. These occupy the outer lower positions in the outlet stack.
6. Place the rear pair of headers in place. Thes occupy the outer upper positions. This completes the rough placement.
7. Lightly tighten all the lower screws to bring the header flanges close to the head. You should now find the outlets all together almost enough to accept the collectors. In fact it may be a good idea to install the collectors now. I have not tried that yet.
8. Start the upper screws in the two inner pairs of headers. You will probably find the rear-inner pair to be the most difficult due to the forward-inner headers passing close "over head". The most common problem for all positions is the screw shaft binding against the hole in the header thus preventing you from threading it in with fingertip pressure. It may help to have an assistant hold the header in whatever position allows the screw to spin into place. Or if you tighten the lower screw the header can probably be persuaded to stay in that position.
9. Once all the screws are finger tight, you should put the collectors in place.
10. Tighten all the screws. I recently purchased a set of Craftsman "ignition" (i.e. "small") combination wrenches (#42319, $20) and discovered that because they are stamped from ~0.1" sheet metal and have a 12-point box end they are absolutely perfect for tightening the header screws where there is little axial clearance above the screw head. Hex head screws should take a 7/16" wrench. 12-pt heads should be 3/8".

 

[Randy V]

Alan this will be priceless to others in your position in the future.
Thank you for compiling and posting!
:thumbsup:

 

[Seymour Snerd]

Revised to make sure the rear two upper screws get started before it's impossible to insert them:

1. It's significantly easier if the lower holes in the header flanges are slotted so the flange can be slid laterally onto the lower screw. My stock SPF headers are like that. I assume here we are using screws, not studs and nuts. Also, I am deliberately not referring to cylinder numbers, but rather will refer to the header positions relative to the each other, while facing forward.
2. Start all eight of the lower screws in their holes in the head. If you do not have slotted lower holes you will skip this step and start the lower screws after the first four headers are placed.
3. Put the four inner headers in place resting on the lower screws. Arrange their outlets to form a neat close square with their ends aligned. These headers form the two inner pairs of outlets and are the ones that do the crossing over which is why they have to be placed as a group. A bungee cord or large rubber band around all four outlets might help stabilize the assembly, although I did not find that necessary.
4. If you are using a Felspro gasket or any other that has slotted lower holes, you can now slide it into place from above.
5. Place the forward pair of headers in place. These occupy the outer lower positions in the outlet stack.
6. Place the rear pair of headers in place. Thes occupy the outer upper positions. This completes the rough placement.
7. Screw the upper screws all the way into the rear two headers on each side. Later on there will not be clearance to start these screws due to the front inner header passing by. The most common problem for all positions is the screw shaft binding against the hole in the header thus preventing you from threading it in with fingertip pressure. It may help to have an assistant hold the header in whatever position allows the screw to spin into place. Or if you tighten the lower screw the header can probably be persuaded to stay in that position.
8. Lightly tighten all the lower screws to bring the header flanges close to the head. You should now find the outlets all together and looking ready to accept the collectors.
9. Start the upper screws in the two forward pairs of headers.
10. Put the collectors in place. You may need to back off some of the screws to give the headers wiggle room to start into the collectors since four individual pipes have to start into the collect at exactly the same time.
11. Tighten all the screws. I recently purchased a set of Craftsman "ignition" (i.e. "small") combination wrenches (#42319, $20) and discovered that because they are stamped from ~0.1" sheet metal and have a 12-point box end they are absolutely perfect for tightening the header screws where there is little axial clearance above the screw head. Hex head screws should take a 7/16" wrench. 12-pt heads should be 3/8".

By the way, as either a historical note or an idea for improvement to the SPF headers, the original Mk II rear-most headers are in two pieces, with a slip joint in the vertical section. The beauty of this is it allows you to put the rear-most header in place before the front most header, even though that's the opposite of the "stacking order" at the collectors. IOW, you get to swap steps 5 and 6 which considerably eases the end of the rough placement, and also, I believe, makes it easier to "collect" all four pipes into each collector. Here's a pictrure:

 

[Robert S.]

By the way, as either a historical note or an idea for improvement to the SPF headers, the original Mk II rear-most headers are in two pieces, with a slip joint in the vertical section. The beauty of this is it allows you to put the rear-most header in place before the front most header, even though that's the opposite of the "stacking order" at the collectors. IOW, you get to swap steps 5 and 6 which considerably eases the end of the rough placement, and also, I believe, makes it easier to "collect" all four pipes into each collector. Here's a pictrure:

View attachment 60378

Very well written and comprehensive. It will serve to benefit others remarkably. I especially liked the nicely worded suggestion to SPF for a possible improvement, that would also be true to the original.

Excellent work.

Robert

 

[Seymour Snerd]

I especially liked the nicely worded suggestion to SPF for a possible improvement

Thanks, but that was intended for the end user. It's a simple welding operation.

 

[John]

Alan, do you know if this is the same order for installing headers on a 351? I'll be doing that project soon and I could use some advice. And, speaking of advice, maybe it's too late in the day but I'm having trouble picturing the headers you term as "lower" and "inner." Do you happen to remember the corresponding cylinder numbers?

 

[DaveM]

John. I found this easiest assembly order on my 427W (351 block):
1. #2L&R
2. #3L&R
3. #1L&R
4. #4L&R

 

[Seymour Snerd]

John. I found this easiest assembly order on my 427W (351 block):
1. #2L&R
2. #3L&R
3. #1L&R
4. #4L&R

Yeah, that's the same logic: basically you do the inner two on each side first so that you can arrange the crossing over at the back among those four with them all loose. Then you add in the rear two, and finally the front two. I just went through this again a couple days ago and was reminded that it may work best to put them all more or less in place before you add any fasteners at all, unless you need the fasteners to hold things roughly in place while you're adding in more pipes. You can also use the collectors for that purpose as well.

Furthermore, if you're really physically adept, I think you can arrange the four pipes from each side on the floor and then pick the whole set up as a group and set it in place on that side, and then do the same at the other side. The trouble is that when you then go to cross over the the "inners" there's some banging and scraping that goes on that you might not like. One of my sets of headers came with each pipe enclosed in thin clear plastic tubing. If you shield them in that way the banging and scraping won't hurt anything. Then you just have so sneak the tubing off when all eight are I place.

 

[Seymour Snerd]

Alan, do you know if this is the same order for installing headers on a 351? I'll be doing that project soon and I could use some advice. And, speaking of advice, maybe it's too late in the day but I'm having trouble picturing the headers you term as "lower" and "inner." Do you happen to remember the corresponding cylinder numbers?

Just by way of explanation, "lower" refers to the lower bolt on any given header (FEs have one bolt at the top and one at the bottom, don't know about SBFs).

Inner refers to any of 2,3,6,7. Outer refers to any of 1,4,5,8. So in cylinder numbers you would first put on 2&3, then 6&7. Then put on 4&8, and finally 1&5.

BTW another thing that will make this easier (at least until you've memorized the whole thing) is to have with you a clear picture of each side assembled, along with a picture looking forward at the pipe exits (without collectors) numbered to show which cylinder goes where. I always forget to do this beforehand and then regret not having with me at the time, so.....

Here are a couple good pictures of the RHS courtesy of P2124 (Grady) and P2125 (Steve).



LHS of HM201 (Lee Holman):



This is how they are numbered looking from the rear without collectors:

 

[John]

Thank you, gentlemen. That's exactly the info I was looking for.