I'm looking for anybody that is pretty familiar with 67 El Camino/Chevelle. I currently have a TH350 but am looking to switch over to a TH400. I know the driveshaft must be shortened, new yoke, but do I need to modify the crossmember at all? And will the TH400 bolt into the same place as the TH350? Right now I use the two middle holes for the crossmember, but have on more back and one more front. Sorry to be so specific. Thanks