cam seized

[Unit 5302]

The valve springs are incapable of creating this problem unless the incorrect springs were installed. Even if they were incorrect, i'm not sure that something else in the valvetrain wouldn't have broken before the camshaft seized, not to mention the valve springs would have caused the camshaft to immediately seize rather than seizing 1500mi into useage.

There is a tremendous amount of force necessary to stop a rotating object like that.

Again, installing the camshaft with improper torquing should have seized the cam immediately, not 1500mi later. I agree that an oiling issue would be more likely, but even so, 1500mi is more than I would have expected there, too. I suppose a cam that was improperly installed resulting in a bend could tend to bend further over time, finally resulting in a seize.

Even though the aftermarket parts do not necessarily come with a warranty, the engine builder is most definitely feeding you a line of crap, and they should stand behind the (faulty in this case) work they performed.