I won't make any comments directly to Jons headers for this engine but will give you a few thoughts/ideas about why some headers are built the way they are-You got to keep in mind that dyno headers are a completely different animal ( sorta like comparing giraffes and elephants neck/nose to maybe hippos and anteaters)-fro m some exhaust system that has to fit in a vehicle---of the 4 or 5 Jerry rules written on my garage wall back by where my frame fixture was is one that says ---------build the car around the headers----build the car around the doors-and a couple of others also but I'll save them for another day----------

When you want to discuss cylinder pairing in a tri y system between makes / braqnds of engines over the firing order, first keep in mind that the 90* v-8s all have a similar CRANKSHAFT but do number the cylinders differently and that a cylinder will fire every 90* of crank rotation but that on some pairings its on opposite sides of the engine and some will be the same side------this creates issues on the tri-y (maybe we should use a different term here, but what we want to do is separate this type from the individual pipes(dragster/funnycar) and the present day 4 tube merge collector-----

I want to interget a thought here about Jons pipes----the engine masters has a criteria of a very wide torgue and high curve so the individual pipes need to be very long------and in my opinion, by using the split exhaust ports, he could really have two lengths of pipes which would widen the curve----------

Over the years cars with FI stacks used lengths to compliment torque curves to aid with the use of automatic transmission (back before they did all the tq stuff((the Fords actually used a 8 inch converter from a Falcon 6 cylinder to raise the stall behind the 427 cammer & tunnel ports)) I don't know what Mopar or GM did as I was a Ford guy!!!!!!!!!!

Over the years ( since 4 -1 collectors) I have done headers to split the firing order into 2 sets of numbers and used 2 lengths of primary pipes to widen the curves out, however it wasn't that I was looking for a wider curve, but was wanting to not create a set of headers that concentrated every thing into one thight corner of the hp corral--------

I found that top fuel headers weren't big enough OD that the pipes would bulge out near the cylinder head---if they were too vertical you could get tire shake, if too laid back, loss of traction at top end and hot tires------ideal size was where a tennis ball would seal the pipe in the trailer/pits-----

I at one point in time (after rear engine fuelers) wanted to run all the pipes up into a large circular collector between the wing structs with a aprox 5 -6 inch center pipe where we would route the return line from the high speed lean out valve that would have created an ramjet/jato rocket type propelsion system but when I sought permission to try it I was pretty much in very few un printable words from people high up in racing told were to go-----------

time for some more coffee-------