Engine choice ? and advice

[Ole Blue]

Making plans and collecting parts for buildup of 72 Cheyenne lwb,could possibly go the swb route. Will be a 4/6 drop, springs in front with bags in rear, 17" wheels,OD trans and so on. This will be a driver and still use the bed for some material hauling, and some towing. It presently has a fresh 30 over 350 (less than 10,000mi.) Thinking of going BB or LT or LS. Looking for informed advice as far as engine selection. BB would be very cool, but since this will be driven on regular basis I wonder if poor gas mileage would dampen my spirits. The driveability of a more modern engine/trans package is appealing, but what about towing (nothing major). I am collecting parts at this stage, so I am flexiable as to the direction that I take. Thanks in advance for all your words of wisdom and knowledge.