All B230F heads should be the -530 head in the US. There is a rare -531 head, but I doubt you will find any in the US. It is a higher flowing head. Stock it flows as well as most ported -530 heads. On a fairly stock motor, however, you may not want such a head. A head from a turbo would work on a non turbo motor. The lower compression ratio of the turbos is derived from different pistons. Camshafts vary, and play an important role in making power. A Turbo cam is too short for high naturally aspirated power. You would want one of the higher performing Volvo camshafts or an aftermarket cam. Putting an aftermarket cam in your stock head might be the most bang for the buck. If you have to remove your head for some reason, you could do some basic work on it then, like a multi angle valve job and light clean up and port matching. If you have to buy a new or rebuilt head and would also be willing to buy a performance cam, you should consider something like Unitek's head package with cam and gasket, assembled and shipped. I think the total cost, shipped is just under $2000. You would probably pay $1200 or more for a rebuilt head, gasket, and performance cam and would get probably 2/3 the benefits. I think there is a link to Unitek from the www.turbobricks.org under links.

Philip Bradley