Originally Posted by Smarty
What is the wheelbase mod?
The wheelbase mod is a hand modification to the rear arms. See post #963 on the MRX4R thread. Link below.
There are a few things to add:
1. Most remove a little material from the lower rear arm by the "up screw" holes to preventing binding against bulkhead
2. Works best with the 4.5 blocks (5.0 and 5.5 need too much material removed from them, weakens arm)