My '40 has the 4spd non-syncro , I enjoy it :)I always use 2nd to start off , 3rd is just for slow corners , everything else is top
With my 245/75 16 tyres and 3.9 diff , 60mph is 2600rpm .
My friend had a hot 235 in his '37 , with the same 4 spd. It did just fine also.
I think , if you are happy with the more precise action needed to properly work the non-syncro 4spd , it will be ok , I also think you might want to be careful with how you treat that diff with the bigger engine you are using .
