Speedo gears question

I am not sure what gear is in my tranny but accoring to www.mymopar.com/speedometer.htm I need a green 31 tooth part #2838931.

My question is I have a new small diameter black 34 tooth and a new larger diameter green 33 tooth that were given to me by the prior owner of my Dart. I was going to try one of them to see if it would give a more accurate speed reading but then I thought is the larger diameter gear for a 727 tranny and the smaller diameter gear for a 904 tranny?

Any help would be apprieciated.
Author: admin