Once an engine is built up[ properly with an original equipment timing cover and a good quality seal, it's highly unlikely the timing cover will need to be removed for quite some time. That bolt arrangement was a holdover from the time that main bearing clearance on the 216's and splash-oiler 235's could be adjusted with shims. It was a lot easier to pull the two bolts from the crankcase side than it was to fight with the front motor mount to get to the bolt heads from the front.
With timing gears (not a chain) that last 3 days past forever, and high quality synthetic rubber lip seals that don't dry out and leak, why would anyone want to pull the timing cover between major overhauls?
Jerry
