I'm Cummins swapping a '74 Duster, thought I'd share the progress.

You might be able to eventually shove that engine in there and make it run and drive but it will never be “safe” to drive on the road. The amount of structure that will need to be removed will make an already flimsy car even worse. Not to mention the weight bias.
Possibly if you are an expert fabricator you could get it strengthened up enough (frame ties, crossmembers, roll cage, etc) to not be a total death trap but by that time you’ll have a ton of time and money in it. But if that’s what you’re after go for it. That’s hot rodding.