If I were you I would concentrate on the 87 GT. It is lighter than the 91 and already has more horsepower. I´m also partial to the 1st gen Escorts too though. If you wanted to work on the 91 though I would definately swap a manual tranny into it if you have the means. Also putting the HO motor in there would be a nice start too. In order to do that though you would have to swap out the computer and wiring harness since the HO isn´t SEFI. If you wanted to turbo your car than leave the LX block in there and just swap the HO head onto it. The reason behind this is that the HO head has bigger combustion chambers whitch when paired with the flat pistons on the LX engine would lower the compression alowing more boost to be run safely. But if you wanna stay N/A with the SEFI engine then you best bet would be to rig the header from the HO motor onto the LX motor. Might be tricky but it is doable.