As DavidB29 mentioned already, the 603 non turbo and the 603
turbo are realy two different engines, more than you would expect when reading the code numbers. As you can read on this board, the 603 turbo in it's original shape has allready problems to withstand his own torque and power.
So I should forget about converting an ordinary 603 in a 603 turbo if I was you!
Just my opinion!