I did this conversion using a 98 Mark VIII/Cobra 4.6 DOHC with a 4r70w in my 69 Bronco, it is not really that bad. I used SCT Pro Racer to eliminate PATS and turn off the unnecessary emissions items. I also built a custom tune for the factory ECM using the tool. You have to know your ECM code and Pro racer locks you to that code but its inexpensive for the level of programming you get.
Let me know if you have any questions, I have a write up over on classicbroncos.com.
68 GT-350 58k miles, Dart 427W FAST EFI, TKO600, full GW front end. This car brought my daughter and I home from the hospital...it will never be sold!
Last edited by dnewman9; 11-28-2012 at 11:53 PM.