[Mike Taylor 3601]

I have always used zinc...that's what Mondello sold....
I buy a ingot of zinc alloy from Mc Master Carr industrial supply it is about 12'' long 3'' wide and 2'' thick will do 2-3 sets of SBC.
Olds might get 2 sets out it..
next set I do I may melt down some old pistons since I accumulate about 6-8 55 gallon drums a year that I scrap...
I have blocked off a SBC intake.. I filled all the heat riser and EGR passages...
intake was cracked under carb so I filled it to prevent vacuum leaks to EGR passages and it has been through teardown....
I think filling head is better to keep heat out of heads