1969 273 upgrade advice
Before I suggest.... are you interested in changing out a torque converter for more stall and/or the rear gears for a numerically higher ratio?
Do you know your gear ratio now?
In general, a modest cam, 4bbl. carb on a dual plane intake with dual exhaust will go a long way.
OE style 340 cam, (or larger) 500 AVS, Performer intake, 2-1/4 (min) dual exhaust with a connecting H or X pipe.
Add a open air cleaner, upgraded ignition, excellent ad on's.