The only issue I can think of is that by using the mechanical fan is as you have said, the radiator will be sitting higher than desired. That then also by time you add the grille surround over top of the radiator, makes the side proportions look horribly wrong with a nose bleed look from the high radiator. Old style electric fans from an early Jappa from the sixties can look ole'school too you know. I use a very early electric fan on mine and absolutely no one has ever mentioned or commented on it and I built my Roadster to be like early to mid 1960's Hotrod.