How much would a fully done slant six cylinder head cost?

Just wondering,I only read and respond about 1th a month when I am not busy.Yes i have dialed my car to what I think is the best.But still believe without Jefferies head and help I wouldnt have a record.Might change my opinion when anyone gets within 1 second of my best run in b/gas.I will being going for A/gas record but will bee 200lbs heavier than the current holder.Then I will add 350lbs and go for Mikes record.I agree it wasnt just the head that got me where I am at,just trying to give credit due to where I think it should go,Guzzi Mark