340 crank with 318 harmonic balancer?

92b said

Are you sure the damper has slipped and isn't just marked for a different timing tab location? My experience is if they have slipped they will continue to slip. Mark the balancer from outer ring to inner hub. In a safe place rev the motor aggressively several times then check your marks.

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I'll try this, but if memory serves we had the timing mark to start with, then it went away. Lol
So I assume it spun.
I'll try this marking and see what happens.

I messaged the engine shop and they reassured me that the engine was balanced correctly for the rods and pistons. They said they deal with this all the time.
I'll order a new transmission mount, I went ahead and bought a 73 spool style trans cross member to replace the current 72 one.
What is the max angle you can have on the driveshaft?

I have the cast water pump/timing cover. It has the timing Mark's on the right 2 o'clock. What year of 340 cranks wont work with this timing mark?