please help quick!!!

ok i am in it deep now and i need help to get out. i recently blew up my beloved 305(86 trans am 5 speed) iam in the task of finding a new engine and i have been told so much shit it is unreal!!!!! i am trying to trade my pontiac 400 off for a 305 that will bolt to my stock 5 speed tranny. i have been told that an olds engine will bolt to my tranny???? is this true. and i have been told that a 301 out of a 79 pontiac firebird formula will bolt to my tranny???? is that true. and last but not least i was told that a small block chevy 305 will bolt to this tranny is that true. i have to have this car up and running by the memorial day parade so if you could help in ANY way please help. i would love to keep the 400 but do to 2.00 dollars a gallon and the amount of driving i do that would be impossible on my income.

a chevy 5.7 , 5.0 and the 4.3 will bolt up to your trans , a pontiac will not