[Backtobasics]

I'm with northboundtrain.
Sell the diesel, and choose some conservative "performance" parts to make the 350 gas more efficient. Moderate camshaft, dual plane intake manifold, carb, headers, exhaust, ignition, etc will wake up the motor. Small block chevy has the benefit of being dirt cheap, so even aftermarket full billet distributors are low bucks.

Air dam or a skid plate during non-plowing times could yield a benefit. I would also look at the back, the rear bumper looks like a parachute to me, what could be done here, to help smooth airflow and decrease the wake?

A wide band setup would allow you to tune the carb better then the traditonal hot rodders... "that sounds about right" methods (I am guilt of this too). It could be leaned out during the non plow season, and richened up a bit during plowing to prevent pinging under load.

Vacuum gauge for instant throttle feedback.