I’ve got a supercharged V6 VT with a stock L67 engine in it which I use for my every day road car. I’m going to rebuild it and put a stage 3 crow cam in it and change the valve spring but besides that its stock.

Unfortunately, the stage 3 Crow cam is designed for a Naturally Aspirated engine and isn't suitable for the L67. We can supply our Comp Cam package to suit the L67, please follow the link below:

http://www.maceengineering.com.au/epages/shop.sf/en_AU/?ObjectPath=/Shops/mace/Products/CAM604/SubProducts/CAM604

Please be aware that when fitting a cam you will need to have the engine tuned to suit, unfortunately, we don't have a mail-order tune to suit a cammed L67. To get the most out of this cam its recommended only for high-end motors, which have been built to rev or have been stroked as the power output with this cam only starts to fall past 7000RPM (less with a stroker) At the very least, modified cylinder heads are required with 130# springs, double row timing chain and given the base circle diameter varies between lobes custom length pushrods are required with aftermarket lifter and rockers.