Hedman makes an "Elite" series header. The steel flange and tubes are much thicker than their super cheap standard headers. Last I knew the elites were priced in the $250 range.

I installed a set of TTI headers on a 440 Challenger, the tubes turned too close to the head bolts and wouldnt meet the head! I called TTI and received a very arrogant response until I sent them digital photos! They offered nothing!
I installed a set of Hookers on my Hemicuda, good fit.
I installed a set of Dougs on a Camaro, good fit.

Best advice..A. thin flanges will leak for sure!
B. unless your building big power use HIPO manifolds!

TTIs are the best set I've owned. A little tight when trying to bolt the #1 and #2 and #4 tubes, but other than that, they went right in.

Ok alot of great advice here but i should give the application they are for. Its a 71 superbee 383 with a/c. The engine has a couple of things done but nothing huge. I was thinking of having headers to keep the engine cooler. On my 70 cuda I had a set of rusty cheap headers on the car and it ran awesome and never heated up driving or at idle. I decided to put hp manifolds on the car and new exhaust. Afterwards I noticed the car ran hotter and there was alot more heat under the hood after the manfolds were put on. Because this superbee will be a nice summer driver with a/c (factory a/c stuff) I am trying to keep the heat down in the engine bay. So I don't have to worry about getting stuck in traffic.

I have read time and time again people bashing TTI headers. My suspicions are that they are rooted in jealosy and frugality. Its like an ugly girl having hatred toward the prom queen. Yes, the TTI pipes are expensive. That may be because they are MOPAR exclusively. NO GM or Ford headers to spread out the production costs. The simple fact is, they build a great fitting product and they charge alot for it.
I have the BB TTI pipes in the Charger. They fit great and do not rattle or hit anything. My car has never been wrecked and I have new motor mounts. The FrankenDuster has a 360 with TTI pipes and they fit perfect too. Once again, this car has never been wrecked and it too has new motor mounts. These two points certainly make a difference in header clearance. Imagine that in an untouched survivor car you have 1/2 inch of clearance to the steering box. Now look at your car. Some time in your cars history it was hit in the drivers front corner. Now you have no clearance and sometimes it rattles. You blame the header company. Our Mopars are blessed with outstanding good looks and rugged engines, but the engineers obviously didnt care much about the enthusiasts that intended to modify these cars. Waaaaaaay too many obstacles in there. The rear steer puts all the steering linkage behind axle centerline for good weight balance but in the way of the exhaust. Torsion bars also helped handling due in part to keeping weight low and toward the center, but they are another obstacle. The LH starter location is a pisser too. With all these hoops to jump through, its amazing to find a company that is willing to take the financial risk to produce these much needed parts.
Finally.... Yes, headers do make more power and the engines sound better. The right size can boost power in the entire rpm range over iron manifolds while keeping the engine cooler. The good headers will cost you, but they are worth it to me.

Actually these Hedman Elite 1-3/4 headers I put on my 63 in 2006 have been great and trouble free. Thick flange and zero leaks. But I just ordered a set of TTI 2" headers for my 63 to go with my new eng I am building. We have the TTI on my boys Dart and they fit good and hold up very good as they have been on his Dart about 10 years and are holding up great and they have very thick flanges.
So I say if you have the money the TTI are a very good header. The Hedman Elite are also a good header but not as nice as the TTI's. I have never used the Doug's but I hear they are also a great header. Ron