To me it looks like you have most (if not all) of the bases covered. Yes, your motor plate will block a LOT of airflow, but lets face it - underhood airflow is NOT a streamlined, smooth-flowing thing anyway.
The combination of big motor plate and no inner fenders, combined with turbulence from wheels spinning in the airflow means all bets are off in terms of predictions regarding efficient exhaust of cooling air from under the hood.
However, your biggest potential trap will be ignition timing. Being either too advanced or too retarded can negate just about any other factor in temperature control.