There are epoxies out there that will perform & hold up pretty good for filling in ports & recontouring.
NOT FOR EXHAUST PORTS
Stuff like JB Weld (NOT JB QUICK) works pretty good,but, it does start to come loose in pieces after a while & you will need to reapply over again.
MBHD
Depends how funny it would be When JB weld gets into the head/cylinders......not the smartest!
I reconsider!
