sorta kinda related.....i put a 270 GMC w/ 50's OD transmission in a '66 van. As i used the bell & trans from the 50's, I had zero commonality in mounts. I cut a hole in the roof over the engine bay, , cut the box out where the flange curved up,(cut another one out of a junkyard van & simply used screws to put it in place) & hung the engine in the hole where I wanted....this made fabbing the mounts easier. the engine was already there, I just had to meet it.
the fan is mounted way too high on these engines- a electric fan off a Benz was aquired. I used a 50's rear crossmember & a adaptor plate, & bolts thru the stamped steel "frame" of the van. It was a king hell lot of work, but I loved that 270.....mutt