You can

Trim out hood bracing

Trim out fender bracing

Trim excess metal from core support

Leave out fender liners

Manual brake and steering

Heater box

Im guessing the granny slant drivetrain weighs about the same as your big block auto. My 83 318 auto longed was 3600

Trim out inner layer of cab roof

Swiss cheese inner rocker and cab mount

Buy lots of hole saws