Engine Swap on A108?

Hey all, I recently purchased a fairly clean 1969 A108 and I want to either swap the stock 318 engine with something like a 400 stroker, or maybe put a stroker into the 318 with EFI. Any idea what I can do with the least amount of modification to the engine compartment, transmission and drive train?

Please point me to the right forum if this has already been discussed!

Thanks!
Joe