There’s these . You will need the later long water pump. https://www.jegs.com/i/March+Perfor...7fZ6mWh72kIBHmt9HasLBpjz2D5d8m0UaAsySEALw_wcB
Crank and alternator will work. Not sure what pump setup will fit this to a 350 if at all. https://www.cvfracing.com/buick-400...q1cav2grd55MGNqokvoTq7_4X8V7gN8IaAhylEALw_wcB