Maybe give these guys a call, they might have some insight to help.
Forrest & Forrest Racing Machine shop
60 Melair Dr, Ayr, ON
N0B 1E0
519-632-1139
They did a plug and redrill from 4 bolt to 5 bolt on my friends Mustang, car originally ran a 302 V8 doing 13.00s 1/4 before nitrous, now has a...