Customs 55 pontiac engine swap questions

haha these pics were taken at my work when the engine got delivered

 

ok, so my next question is on transmissions. i know i would need to have the flywheel machined in order to keep the 55 trans. but does anyone know if a 56-58 pontiac trans will mate to the 59 crank. meaning will a flex plate from 56-58 clear the back of the crank and if the 58 trans mounts are in the same place. i have located a 58 trans which has side mounts but im not sure if they are in the same location as the 55. and id like to not buy it then find out it dont work?