That brings us to the firing order. Now all things being equal, the most efficient firing order is that of F1 cars more or less – which is 1-5-3-7-4-8-2-6, with some slight variations on that.  The important thing is that no two adjacent cylinders fire sequentially; i.e. no, 1-2. 7-8. 6-7. or so forth as with most major automakers. (Note: all firing order references are to one bank numbered 1-4 and the other 5-8.)  Now, the theory behind this is that when one cylinder fires, it will heat up the cylinder wall, and expand the cylinder; albeit a minuscule amount, but it expands nonetheless.  This produces a problem in reference to the cylinder next to it when it fires.  First is the fact that now it has to squeeze through a smaller bore due to the expansion caused by the other cylinder.  Secondly, it will be dealing with a heated charge of air due to the rise in overall temperature due to the common wall/combustion chamber areas.  Thirdly there is the matter of undue stress on the cylinder wall as it is rapidly forced one way and then must change direction to push 180 degrees opposite.   This is why the firing order of an engine is important in the makings of a race motor, and some things that were taken into consideration by the high rpm crowd of F1 guys.  It is also something that is of interest when trying to understand just what a motor does.  There is also a lot of involvement with intake runners and fuel charges when dealing with firing orders, though a lot of that is only a carburetor discussion; mass quantities of it can be ommitted for the Sequential Port Fuel Injection crowd.

This is why in some performance operations people opt for a cam that “swaps” a couple of cylinders on the firing order, such as a 4-7 swap on some Chevy’s.  It has to do with the increase in power garnered from the correct usage of the available fuel charge and the increased efficiency of the engine overall.

First off we will look at the points style, simply because if you understand how that works, the others kind of fall into place.  There is a point gap that needs to be set, and the factory gives a specification (heretofore referenced as ’spec’) for the particular engine/vehicle combination in relation to a dwell angle.  Now the point gap is simplhy how far the points open at the high point of the cam on the distributor shaft.  The dwell angle is the amount of time the points are closed, allowing the coil to “recharge” as it were for the next discharge. The dwell angle is more important for tuning than the points gap, but both should be set in conjunction with each other.  To set the dwell necessitates the use of a dwell meter, and it helps to have a tach handy, which is usually part of the dwell meter.

Now that we know that little tidbit, point gaps are usually set around 15-20 degrees and the dwell angle varies upon engines, but for a V8, look for around 30; as I said, the factory has specs for the particular set up.

Once you have stabbed your distributor – that is installed it in relation to the #1 cylinder on top center with the rotot lined up on the #1 firing position – you will need to set the points and dwell; as long as you are not too far off on the overall engine timing.  Once you get those set you can set the overall engine timing specifically where you want it to be, or where the factory says it should be, whichever the case.  That needs to be done with a timing light and tach, just for reference on the latter.  Now, to figure how soon the timing comes in on the power/rpm band, one really needs to fool with the mechanical advance on the distributor, assuming that is the set up. On a lot of the older Fords, the process is slightly more difficult than some of the newer aftermarket models, but the overall concept is the same; in order to bring the timing in later one needs to add heavier springs, in order to move it in sooner one should add lighter springs.  However, a troublesome problem will arise if one fails to have tension on the springs in the first place, so make sure the spring attach points are adjusted outward enough to fully engage the springs and put a little initial tension on them.

That said, the total timing of the engine is the initial timing plus the advance timing, which should run you somewhere in teh neighborhood of 28-34 degrees or so, depending on the initial and where the stops are for the advance.  The Vaccuum is actually there just as a fuel economy thing, and may be capable of being adjusted, however, at Wid Open Throttle (WOT) it is doing nothing, seeing as the engine produces virtually no vacuum there, so for tuning it can be all but omitted.

Once you figure where you want the timing to be, you can go about the rest of the tuning of the engine; i.e. carb settings and mixture.