I rebuilt my motor and i put 20 over pistons in it. Thats as far as it will go. Whatever you do dont get them port and polished becouse it doesnt do anything for it. It only adds 14cfm to them its not worth the money unless you realy want every horse you can get. If you want get the valves backcut and seats regrinded, this will decrease valvetrain weight and let the engine rev better. It will also increase cfm into each cylinder about 4 cfm. You can also get the crank shaved down .030, this makes less friction on the crank and it will rev quicker too. Take the connecting rods and go to a machine shop and get the extra weights shaved off the top and bottom of it, and balance them and the pistons. Also you can get the heads milled down to up the compression, but you have to be carefull that the heads arnt warped becouse it will mees them up if there milled. I also know some more about it if you want to email me about it...i know what im talking about too im a machineist who loves 300zx's and i know a lot about the VG30E engine
ohhh yeah it cost me about 1,700 for total rebuild
Email me at
EvaR2004@Aol.com