Why does your right-turn signal on your 1997 Chevy Venture still flash twice as fast as your left one after you replaced the burnt out bulbs All the bulbs appear to be working properly now?
most people do not think to check the polarity when changing the blinkers, try rotating the flasher bulbs that you changed, do one at a time until you see a difference in speed from the flashers.
Also check that ALL of the flashers are working - including the "side markers" on the front side AND the parking light bulbs in the very front. ALL of these have to be working for the lights to flash at the proper speed.
I would also check the "brightness" of the bulbs between the two sides. If one side looks dim, then that would point to a wiring issue.
Good Luck, Greg