Below's a link to the Speedtech Chevelle Cover. At the very bottom of the page is instructions that may give you a better idea if it'll work or not. One nice thing is that it goes the length of the tunnel so it will give you plenty of room for a raised drive shaft and proper pinion angle too. It also includes a panel that goes in the trunk for ExtReme chassis frame rail clearance but isn't necessary with a factory frame. Unfortunately we don't sell the kit without this panel. Photos on our web page show it installed in a 69 GTO.
Click Here for the Chevelle tunnel kit.
If you only needed the front piece that goes directly above the trans you can buy the Camaro one, it's similar only the Camaro doesn't need the front firewall portion, the rest of the tunnel behind the trans and the rear trunk portions so it's less $.
Click Here for Camaro Tunnel cover.
The Camaro tunnel cover can raise the height of the tunnel upwards of 3.5". The Chevelle cover will raise the tunnel upwards of 6". Now supposing our tunnel cover isn't tall enough, it may make more sense to get it anyway and fill the gaps along the bottom sides between the cover and the car's tunnel with sheet metal instead of rebuilding the whole tunnel from scratch? I don't have a diagram with measurements for the Chevelle cover parts yet. For the dimensions for the Camaro cover
Click Here I'll post it here when I get measurements for the Chevelle cover.
Good luck with it and feel free to contact us with any questions!