Timing Chain Cover crankshaft opening is the wrong size

But only with the cast crank 340/360 engines, which each had their own unique balancer. 318s were all internally balanced regardless of whether they were cast or forged crank, and used the same balancer 9with the timing mark and bolt hole differences already noted).
Thanks for the info as it's a 318 block and it's been running smoothly the timing chain cover is all I need to worry about along with a cast wasterpump. The timing gears and chain were replaced when it was rebuilt ( No plastic gears)