I just put one in my car about a month ago after changing rear end housings (original gas tank would not clear the back braced rear). Couple of things to keep in mind before you start cutting if you are going to take this to the track:
1. You have to box in the sump with steel if it is outside of the body (see NHRA reg below). It is easier to put the fuel cell on a pedistal in the trunk and run the lines out the floor, rather than cutting a hold and building a box to protect the sump (I thought of this AFTER I cut my trunk :banghead: ).
2. You have to build a rear firewall to keep it NHRA legal (see NHRA reg below).
From the NHRA rule book:
General Regulations 1.5
Tanks: When permitted by class regulations, fuel tanks located outside body and/or frame must be enclosed in a steel tube frame constructed of minimum 1 1/4-inch O.D. x .058 chromoly or .118 mild steel tubing. All fuel tanks must be isolated from the drivers compartment by a firewall, completely sealed to prevent any fuel from entering the drivers compartment. All fuel tanks must have a pressure cap and be vented outside of body. A positive-locking screw-on fuel tank cap is mandatory on all open-bodied cars. Insulated fuel tanks prohibited. When used, fuel cells must have a metal box protecting the part of the fuel cell that is outside of body lines or trunk floor, excluding hose connection area in rear. The metal box must be constructed of minimum .024 steel or .032 aluminum. Nonmetallic fuel cells or tanks must be grounded to frame.
I hope this helps.