I do these as a living.....12.7 liter Series 60 Detroit has a kit for a cost of about $2875.00..not including the head or other incedentals. We do the head for $1500.00 and check everything else and the total cost is around $12,000.00.....Cummins is around $13,500 for ISX, $14,000 + for the ISM...