My current 350 had staggered pattern. I actually had to go the other way to the inline when I did my manual trans swap. Only my block is from a 9C1 Caprice and was never drilled for both starters. I made my own drill guide template and drilled and tapped my engine block for the other bolt pattern. Now I run a factory mini starter from a 94 Impala SS. That's why I like Chevy's you can mix and match parts from a span of 3 or sometimess 4 decades. My engine is a 74, bell housing from a 69 DZ302 Camaro, 68 Camaro transmission and it's connected with an 85 Camaro flywheel/clutch