Stroker 21 stud

[KiWinUS]

Guys looking for input here ! I have a 37 core engine .
I was talking to a very good friend on mine last Friday (well known flathead builder from LA) about building a 21 stud to put his NEW Sharp heads on (I have a very large collection of Sharp speed equipment) & he suggested I put a 4in Merc crank in it . Well after some thought , I would have to grind Merc crank mains to 37 size , cut the counter weights down plus grind rod journals down to 2" , use a set of NOS 21A rods so all of that comes with a nice bill from my crank guy .
So here's what I think I may do , take a 37 crank (I even have a NOS one) have my crank guy weld the rod journals & make it a 4" crank , he confirmed today that he can do that for me no sweat .
I would bore it to 3 3/16 & of course it would get the "Famous" KiWi-L100 cam!!!
Th 37 crank I believe would be way lighter I believe (Brian from NZ will like that !)
So what do you think guys ????
Cheers
Tony