Compare the Iso Grifo GL 300 5.4L V8 - [1965] vs Mercury Cyclone 6.4 V8 - [1966]. Find out which car is the fastest, most powerful, lightest or has the biggest engine in our top trumps style comparison page. Find out which car has the highest top speed or is the fastest accelerating, is it the Iso Grifo GL 300 5.4L V8 or the Mercury Cyclone 6.4 V8. We'll leave it up to you to decide which is your favourite.