The seal surface on a 216 crank is 3.875" OD x .645" thick. Those dimensions should get you the right speedi-sleeve PN by checking HERE. I believe this one would work.
I think you'll be a little shocked at the cost of one that size, but I may be wrong. I went with machining the block for a full circle lip seal instead.

Last edited by klhansen; 09/19/2025 9:51 PM. Reason: added amazon link
Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.