Here is my update. I used a NAPA electronic flasher in the turn signal circuit. It had to have a ground wire attached, but that was no trouble. I also used a LED bulb that was the 1157 equivalent to replace the existing turn signal bulbs in the rear of the car. The result is exactly what I wanted. The bulbs flash rapidly and brighter.

Thanks for all the input from the forum!

Charlie

Just in case someone reads this thread,  I bought these on Amazon. They arrived today, and I installed and adjusted them. The only drawback is that they are silent, so it might be easy to leave a blinker on.

 

http://www.amazon.com/gp/product/B011BTMDQM?psc=1&redirect=true&ref_=oh_aui_detailpage_o07_s00