I accept that there are lots of great parts outside of the US. We base history on our history, it's great that we have a world wide economy now.
The Aussie Clevelands from what I've read had 2V heads with closed chambers, which would be about 64cc. Cleveland heads are great, but the 4V versions are too much for the street.
For the Explorer it would likely take stock exhaust manifolds to fit them in. I wouldn't do it just because of the many parts that are unique, plus the need for a carburetor. So much more can be done with fuel injection and Windsor parts. I'd like to build a 351W some day with aftermarket Cleveland heads, and a 4.0" stroke, FI and supercharged, using a 96-98 PCM. Good luck,