C-4 Overall length 30-3/4" Face-to-mount distance 20-3/4"
C-6 Overall length 33-1/2" Face-to-mount distance 22-3/8"
AOD Overall length 30-3/4" Face-to-mount distance 22-3/8"
AODE Overall length 31-3/16" Face-to-mount distance 19-3/8"

You are going to find issues in fitting it to your 460 in that it will need a quicktime bellhousing adapter (RM-9011)

Yes to the enlargement of the firewall/transmission tunnel for clearance

Bill S.