8 bolt? are you talking about a 351w or a 302 w? or do you mean your 4.6 was built in windsor ont? i have never heard of 8 bolt crancks. i know the cobra came with a 6 bolt.
Well.. right and wrong. the windsor block I just got has a 6 bolt crank, but it is a truck flywheel pattern. 2 offset bolts instead of just 1. yes cobras all have 8 bolt. the main difference between win. and romeo are the main caps. the windsor has extra support. i wouldnt call it a 4 bolt main,.. but close