If two cylinders on the same bank fire sequentially (i.e. 8 & 4; 5 & 7 on a stock firing order), then the tubes from those cylinders should be across from each other in the collector, not next to each other. Not sure that it makes much difference though, in my opinion.
Main thing is to study the firing order, and clock the collectors accordingly. You don't want two pulses trying to go through the 'Y' at nearly the same time. If the two cylinders fire one right after the other, it could hurt power. Try to pair cylinders that fire opposite each other as much as possible.I'm Picking up a set of headers, their 2" came off a 67 fb, I'm gonna use them in my 74 fb. I've cut my cross member out quite a bit and am using motor n mid plates so i'm hoping they'll fit without too
much tweaking, they also have 4,2,1 merge collectors on. How much would it hurt these collectors possible gains with full exhaust on as that's what i run, but i plan on making it possible to drop off the full 3.5 X for next season to see if any gains are possible
I've got the LS firing order in my Pontiac and these headers are clocked with the traditional firing order as the tubes haven't been moved around, The guy them with the merge collectors on already and he ran them that way.Main thing is to study the firing order, and clock the collectors accordingly. You don't want two pulses trying to go through the 'Y' at nearly the same time. If the two cylinders fire one right after the other, it could hurt power. Try to pair cylinders that fire opposite each other as much as possible.
I installed a set of 4-2-1 collectors decades ago, and ended up with one horizontal and one rotated 90 degrees. Seemed to work fine. I welded header rings to the ends of them, and ran them with a 3" exhaust.
Hooker use to sell some really pretty ones with nice, smooth Y's... Flowmaster also made them, but they weren't as smooth. I'm pretty sure the Hookers have been discontinued, but haven't checked on the Flows for a while.
Picked up the headers today, Drivers side is 1753, passenger is 8624, So i'd have to change those two pipes in the passenger collector correct, Or is it not as important to fire in a circle since these have merge collectorsHow about this , use a clock for reference as in 12 , 3 , 6 and 9 oclock . 18436572 firing order , 1357 and 8462 following around the clock as in 1 @ 12 , 3 @ 3 , 5 @ 6 and 7 @ 9 oclock . Swapped order : 18726543 , 1753 and 8264 .