Technically long tube equal or un-equal lenth headers will let the engine "breath" the best, delivering more power. The down side is they can be hard to install, won't directly hook up to a stock mustang dual exhaust, possible ground clearance problems and there can be interior heat issues.
Shorty headers won't give you as much "breathing" as long tubes, but in most cases will hook up to a stock Mustang dual exhaust system and are generally easier to install than long tube headers.
The difference between equal lenth and un-equal are the lenth of each tube. On equal lenth headers all the cylinder tubes are the same lenth, so the headers will have tubes twisted in all sorts of configurations to make them fit to the collector. On Un-equal headers the tubes range from longer to shorter giving the appearance of a smooth tube arangement to the collector which in most cases makes them easier to install and change spark plugs.
The idea with equal lenth headers is that each cylinder will have the same amount of back pressure to the collector. On un-equal the pressure will vary from each cylinder to the collector.
IMO unless you're looking for the most power and plan on racing a lot than long tube would be the way to go. If it's mostly a daily driver with a couple trips to the strip per year than shortly un-equal would be better.
There are a lot of different thoughts on which one is "better", you just need to figure out which type will suit you best.
Shorty headers won't give you as much "breathing" as long tubes, but in most cases will hook up to a stock Mustang dual exhaust system and are generally easier to install than long tube headers.
The difference between equal lenth and un-equal are the lenth of each tube. On equal lenth headers all the cylinder tubes are the same lenth, so the headers will have tubes twisted in all sorts of configurations to make them fit to the collector. On Un-equal headers the tubes range from longer to shorter giving the appearance of a smooth tube arangement to the collector which in most cases makes them easier to install and change spark plugs.
The idea with equal lenth headers is that each cylinder will have the same amount of back pressure to the collector. On un-equal the pressure will vary from each cylinder to the collector.
IMO unless you're looking for the most power and plan on racing a lot than long tube would be the way to go. If it's mostly a daily driver with a couple trips to the strip per year than shortly un-equal would be better.
There are a lot of different thoughts on which one is "better", you just need to figure out which type will suit you best.
