This is probably completely wrong, but is it the B-17? Its flown with radials, normal (merlins or alisons i cant remember, this configuration kept bursting into flames because of cooling issues) turboprops, theres photos (maybe photoshopped) of one flying with a single turboprop. And im sure there was some that had mixed engine types.
Like i said, im probably way off mark though. Probably got the time period wrong too.