OK so you want and O/D first question is what rear axel ratio and tire diameter are you planning to run .
Once you figure that out you may not need O/D.
You may have a 2.94 or 3.23
Depending on tire diameter 24" 25" 26" 26.5" or 27" you nay not need O/D
I have P205 65R 15 in my Dart now with 2.94 gear and /6 904 , running around town I don't need 3rd its to tall . I will be changing to 3.23 gears and this should help. (see picture)
My only performance add is 2 1/4" exhaust from manifold to tail pipe with a muffler .
This made a big difference on the freeway lots of power . This was with P 225 60R 14 and 2.94
P 225 60R 14. 24.7" dia. 842 rev's per mile
P 205 65R 15. 25.4" dia. 817
P 245 60R 15. 26.5" dia. 781
View attachment 1715639445
