The first thing that comes to mind is, what is the temerature at the plug when it dies? If it's getting hot (250+), then that's why it's a pain to restart. If it's still cold (200-), then there's a fuel flow problem. Changing the head might affect the temps some, but it's more likely that changing the pipe would affect the fuel flow more. Does the engine act like it's getting too much fuel, but not enought to flood it? One trick that works for me is to stand the Savage on it's tail to start it if it's acting like it's flooding. When you do this, the fuel tends to drain out of the crank case, into the cylinder and out the exhaust port, and then starts up. be careful not to vapor lock it though.
A couple of other thoughts. Do you use an inline fue filter? crap tends to clog the HSN is you don't, and that might be one source of problems. How much time is on the glow plug? If it's getting old, it won't run right. And is the air filter clean and lubed?