In the process of building a 16 valve turbo lump for the gti-6, i have the turbo ready and have fabricated the manifold already, but i would like to use the 406 SRI turbo block, now i read somewhere there are two types, one with dished pistons and one with flat top pistons, now i believe i need the one with flat top pistons but I'm not entirely sure. Can anyone point me in the right direction and give me the correct engine code so i source the correct engine! Any help would be greatly appreciated, Regards Dan.