Ok so I ended up downloading the parts catalog off line and figured out how to use it lol. So I found the part numbers for the crank and drive link to covert the 72-74 E-body to 3 speed wipers. These come right from the original parts catalog for E-bodies years 72-74:
Crank - Part# 3431 518
Drive Link - Part# 3431 514
Ended up picking them both up for 90 bucks on eBay. So I guess I didn't make out too bad...
Also since I was there I wrote down the 3 speed motor part numbers for 72-74 in case anyone wants them. These come right from the original parts catalog. The number for the switch is also listed below. Motors are as listed:
For 1972 Models:
Before September 1, 1971 - Part# 3431 534
After September 1, 1971 - Part# 3431 624
For 1973 Models:
Before February 1, 1973 - Part# 3431 624
After February 1, 1973 - Part# 3431 665
For 1974 Models:
All Models - Part# 3431 906
The switch is the same from 72-74. Part# 3621 670
Thank you all for your help! Hope this post helps someone!