[capev86]

put in an overdrive trans with that 3.73...200-4r is a bolt in for a turbo 350. the effective top gear ratio will be around 2.61. that means you will have awesome highway cruising AND better get up and go. a lockup converter is another good idea....save every last rev and reduce trans temps.

my dad swapped his 87 burb 2wd over from a 3.08 to a 3.73. it already had OD and so he "maybe" lost 1mpg. the weight, aerodynamics combined with new england hills may have been too much for that soft rear gear to handle. it still pulls of 18mpg. i say...have your cake and eat it too!