My opinion is if this is the only CMP you're going to own then one of the most charming things about the breed is the melodious sound of the engine and gears in low range - sheer music which only sounds right with the original drive train.
As for power - a car-size engine in a heavy truck is never going to break speed records, but I've lived with this for many years, along wiith the joy and pain of 6 volt electrics - none of this is practical for an everyday driver but that's not what it's about for me.
Having said that, because we (Euan and I) have so many CMPs between us there is no compunction taking a F15 and putting a Windsor with C4 in it. Likewise, Euan's CGT came with a Mexican Chev mated to the original gearbox which gives it good performance; he still has an original C15A with the stovebolt.
My FGT will be as original as I can make it - the only possible change may be to 12v so I can see at night...
