Here is a video tutorial on how to upgrade your old 7slot PCI expansion chassis.
In the video we are using the PE6NE-I board set upgrade kit.
Also, this video tutorial applies to 7slot 64bit/33Mhz and 13slot 32bit/33mhz.
And if you have an old PE6R4 ( with two cables) you can do the upgrade as well.
1. If you have an old 13slot unit you can still do the upgrade using the PE6NE-I board set upgrade kit plus an additional back slot panel.
2. if you have a new MacPro Intel computer and you would like to use a 7slot 64bit/33Mhz Chassis ( with two cables), it is not going to work at all even if you replace the host card with a PCIE host card. And that's why you need to upgrade it.
WHY? The chip (which is DEC) on the 7slot 64bit is not compatible with MacPro.
Also, old 13slot expansion chassis uses the same old DEC Chip.