Hi i have a 91 240sx with the stock KA .Today i got a call from the mechanic saying i have a cracked cylinder head. He said he filled it with liquid glass but he dont know how longs its gonna hold up. My question is what would be my best option. I was thinking to get it replaced but would i have to rebuild the motor when i do this? How much would labor be? Would i be better off just getting a new motor? Any help is VERY much appreciated. Oh and it is dohc. Thanks