yeh good advice, head work at this level really does have many advantages, sure cams are handy but pricey and at this level not really essential. Some port and polishing is usually a nice way to go and just rebuild the head. No need to really go to nuts on the head unless you are planning to do other things. Why have a nice freeflowing head if you have a restrictive inlet plenum and exhaust manifold?

The beauty with the cossys is that you can realisticly aim anywhere up to 400 with pretty much a standard engine, just changing the littlebits around it. Injectors,decent turbo blah blah. Make sure you slap a decent head gasket on there and maybe even long stud it for extra safety. U cant go wrong here.