Best Long tube headers

it depends on what you use the car for. for a driver and can see how a collector leak is annoying. my mustang is a tagged and inspected street car, but we have other cars to drive so I just run copper gaskets or just silicon at the collectors depending what I have laying around. now that I think about it I haven't even started mine in 2 weeks. back in '98 I had the turbo technology street kit on mine when it was a daily driver. It would blow header gaskets at the flange of the turbo header. talk about a pain in the ass. the coppers seal pretty well, then George Scott of TTI told me to try the super high temp silicon. it does great as long as the surfaces are true and the bolts stay tight. you could always cut down the 3 bolt collector on the longtubes to make it round, then butt the pipes together and run a dynomax band clamp. I used those on my downpipe they work like magic considering they dont crimping the pipe.

like you I hate the mac headers, why they don't run a thick single flange on the primaries rather than individual flanges is beyond comprehension.

I had the ball and socket of a 3" X pipe welded onto my Kooks headers and new H pipe. Then I assembled the exhaust, marked the ball and socket with a marker, took it back apart, and took a grinding wheel to enlarge the ball opening where it looked feasible. It's a compromise, but I'm with Gearbanger that it's nice to have the ball and socket assembly.

My '69 F250 with .030 over and warmed up FE390 with cheap FlowTech long tubes would blow a gasket on occasion. Never gave it much thought to be honest cause it took 5 minutes to pop a new one in. So you may well have a point about gaskets.
My '92 LX on the other hand I guess was an anomaly running hooker long tubes, matching Hooker H pipe and cheap Mr Gaskets for a little over 3 years daily driving at the time (and racing nearly every weekend on my quest for stock motor 12), and never once lost a gasket.