Basically fitting an Olds engine is going to require you to custom build the mounts. You could have issues with the oil pan not allowing you to lower the engine low enough to allow your trans to clear the cab floor. If that is the case, you are going to have to cut and weld the floor to fit.
If you were using a SBC, you could buy everything to allow it to bolt in without mods but you're going to have to do a full custom fab job to make this work.
On a side note, I never knew that GM used Olds blocks in Chevy vehicles. Learn something new.
