"427 engine sound you can feel"

[Charlie]

This is NOT a discussion about big blocks vs. small blocks! But during a recent such argument, one of our Cobra buddies made the comment that he liked the 427 because of the sound . . . that he could feel it as well as hear it. He reasoned that it was because of the uneven firing. So that got me to wondering. . . what is the comparison of firing sequences for the popular engines, and could this lead to a difference in perceived sounds? Assuming we have true dual exhaust like in the Cobra sidepipe arrangement, the sound we perceive will depend (in part) on the left-right sequence of firings, not the sequence of cylinder firings. The left sidepipe does not care if it was the number 5 (front) cylinder or the number 8 (rear) cylinder that fired, it will sound the same in that sidepipe, but the relative sequence of other firings in that same sidepipe COULD make a difference. The results are clear, we will need to find another reason to like one engine over the next. Here are the firing orders of the popular engines plus the left-right sequence of pulses:

Ford 302 (early) 15426378 RLRRLRLL
Ford 351, 400 13726548 RRLRLLRL
Ford 427 15426378 RLRRLRLL
Ford 429, 460 15426378 RLRRLRLL
Ford 292 15486372 RLRLLRLR (I threw that one in just for fun!)
All Chevy V8’s 18436572 LRRLRLLR

These would all appear to be different, but if you repeat the sequences indefinitely, as in an engine that is running, you will see that they all follow the same pattern. You can start it anywhere you wish, the pattern is the same for all the engines . . . RLRRLRLLRLRRLRLLRLRRLRLL . . . etc. The firing pattern of these engines cannot be responsible for any perceived difference. So what is it? Exhaust system? Seems likely to be a big factor. But my 351 has a free flowing exhaust and is very loud, but it doesn’t pound me in the chest. Cubic inches? Big c.i. would seem to relate to more “feel” in the chest cavity. But the old 460 Lincolns would purr like a kitty, not pound you in the chest. So c.i. alone can’t be it. Radical cam? Possibly, but again I submit my 351 SVO with its fairly radical cam profile. That funny car at the drag strip just about knocks the wind out of me, so what does that have that all these other scenarios don’t ? Plain old horsepower! I submit that is the real source of the “feel it as well as hear it” effect that we gear heads love so much. If true, any of these engines with equally high levels of horsepower should produce the same effect.