Speedometer Gear for 4.10 gears

[WPE]

      Ok I know this has been asked before, Can anyone tell me what Speedometer gear to use to correct the speedometer so that it shows the right speed :: I have a 4 speed 72 Dodge Challenger with 4.10 and 295 50/15 tires.
      Also, It seems that thier was a production change in 72 for some parts, I cannot read the production date on the door, Is there a way to tell if it was made bofore 3/72 or after.

Thanks -Fred

[heminut]

I have 275-60-15 tires and run a 39 tooth gear in mine.

[AprilsPink72Cuda]

Here is a link for you.  It is to figure out what tooth gear is needed.

http://clubs.hemmings.com/clubsites/cowtownmopars/Specsheets.html

[OUTLAW]

here is another

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4513090702&category=34208&sspagename=WD1V