legacycentral bbs

anyone know the answer to this question?
G

They are interchangeable, but valve sizes are slightly different and cam timing is different. N/A heads also need to be drilled and tapped for the turbo oil and coolant lines, though the area that needs to be drilled is obvious. It appears to me that the heads were made all the same and they only machined/installed a few things differently as needed. Either head type could be used for either engine. I'm running (or was until I parked the car) a turbo engine as N/A and the performance difference between the ringer N/A it had previously is mostly gas mileage and top end power reduction, but most people would probably not notice were they not informed and I attribute the biggest percentage of the performance change to the lower compression than the heads.

The cam shafts are different too