The only 427 blocks that I have seen with that area cut away was on a marine engine. My 427 was cast in 1970, and I am not sure if it is a service or an industrial block, but it is a hyd. lifter sideoiler block, with no such machining in that area. I do know that when I went to install it in my Fairmont, I had to modify the driver side motor mount, since the bolt spacing was different, to accomodate the side oiler bulge. Maybe these marine blocks are cut away to allow the lower motor mount bolt hole remain in the normal non sideoiler location. Has anybody ever measured the motor mount bolt pattern between the sideoiler vs non sideoiler 427 blocks?
428 powered Fairmont drag car, Best ET:9.97 @132.56MPH, best 60 ft: 1.29
59 Meteor 2 dr. sedan 332, Ford O Matic
74 F350 ramp truck 390 4speed
1985 Mustang 331 4 speed Best ET10.29at 128.7mph, 1.40 69 foot