ZZ4 for 2005-sesongen

My new race engine , step by step update. This is as it came from the machine shop, but I have added the register , harmonic balancer and the oil pump.

As you can see , it is balanced and weighted pistons and the crankshaft. Of course the job has been done by a specialist. Notice the next picture , showing the drilled holes on the crankshaft. This shows clearly that the crank needed this...badly ! The engine was originally a ZZ4 engine and they are very good. However , it is always room for improvements ! (link to GM Performance here: http://www.gmpartsdepot.com/zz4crate_engine.html ),

I have used TRW forged pistons , about 8,7:1 compression rate. Originalt it is 10:1 with "high-silicone" pistons. This has been done because of the supercharger.Of course you need lower Comp. ratio if you want to have higher boost pressure from the supercharger. Also I have mounted a new cam from Crane , and I added 1:6 Roller rockers. More pictures and text will follow !