I know when welding aluminum it is best to preheat the part. I am having a local welding outfit do some work for me on a set of aluminum heads. They will be welding on some intakes I made for IDA Webers.

Question 1) Will they preheat my heads before doing any TIG work?

2) Should they???

3) How high temp?

4) Do I need to strip my new valves, springs, and seals before taking them?