[68gmsee]

Yes they still reproduce them or look on ebay. If you're a member you can post a want to buy in the parts section of this site.

As for welding, there are some places that can weld it for you. They have to specialize in the sort of work. Used to be they'd have to heat the metal to a certain temp because cast iron tends to crack fairly easy. I've heard of some that can braze it with good results. I have used metal set before with decent results.

I have a leak in my gasket between the carb and exhaust and the engine runs fine without a miss. Check your ignition again. Maybe use a timing light to observe the spark of the different plug wires. Do a compression test also to make sure there isn't a burnt valve and check for vacuum leaks carefully.