just bought a cuda with a set of hedman block huggers----every tube is cracked at the collector area-----and someone had to dent one collector to keep it off the ministarter-----speed shop guy said throw them away--they all crack....this car was a daily driver and sometimes saturday racer-- dont know how many heat cycles these headers went through---but they didnt hold up well......
"they all crack"??
If you look at the way block huggers hang, its not real surprising there may be a cracking issue.
Standard headers tend to hang straight down from the exhaust ports, where the majority of the weight of the block hugger headers is a few inches inward of the exhaust ports. That would put the strain of the header weight on the tubes at the bottom of the tubes, and would cause the flanges to bow inward at the top, and outward at the bottom of the tube flanges. Picture the block hugger trying to hang straight down instead of bending in.
Usually, all header collectors are connected to pipes the are held stationary under the car. With normal headers, the weight is hanging straight down off the exhaust bolts, so the collector and pipes are hanging without stress. Since the block hugger headers are already trying to move away from the block, the collectors and pipes become another stress point that is caring the header weight, something they were not designed to do. Eventually, all that stress will create problems for the weakest point, probably the collectors and/or the block flanges. Then you add in a few years of heat cycles, the the header material becomes brittle, the collector is more subjected to the heat and cool cycles then the flanges are.
Probably a support bracket for the block huggers about the bell housing area would help relieve some of that extra stress, but I'm just speculating, I have no real life experience to back it up. Gene
