An in-line filler cap is added to the upper radiator hose and a separate oil cooler is mounted in front of the radiator. Use the overflow tank from a Monte Carlo and mount it on the inside fender, drivers side. Nova and an aftermarket flex fan. The single biggest thing you can do for Z car cooling is to properly duct and shroud the fan. Numerous things can be done to decrease the additional weight.
Headers Move the Battery to the back.
Brodix makes one. That should make the weight about even. A lot of people who have done the V8 conversion have found that they need to do some level of modification to stiffen the chassis. The following is a list modifications that have been suggested on the net. This should eliminate the torquing of the body shell due to engine torque, since the reaction torque to the driveshaft will go through this torque-tube instead of the body between the motor and diff mounts.