Hey guys, need some help. I need to remove the dowel pins in the block that locates the bell housing. I have a scatter shield and I dialed it in but I need to replace the pins with longer ones so I can weld on locating washers to the bell housing. The pins in the block seem like they are welded in

I wonder if it is worse because I have a aluminum block with steel pins...
Anyone have an idea on how I might get them out? I tried heating them, grabing them with vice grips but nothing works. Can't even get them to rotate. I have a big slide hammer but I need to attach it to something. I thought about welding a bolt to the pin but that seems sort of drastic. Also thought about drilling a hole in them and then seeing if I can tap threads so I can put a bolt to pull on with the slide hammer, but again pretty drastic and the pins are REAL hard.
I am out of ideas. If anyone has any ideas let me know... help!
Thanks,
Russ