Just a tip ,
If you go with the firewall mount Booster ..save yourself a headache down the road and FAB up a backing plate a bit bigger than your booster on the engine side and add some support bars .....on the inside.
in my expierience the stock firewall is too thin and after yrs of pushin the pedal you will get stress cracks an eventual fail of the firewall metal .
Xtra support is needed to carry the weight of the booster/master and stress of shovin the brake pedal to the floor for STUPID HUMANS that WILL pull out in front of you .
just a heads up
Tim