NEED HELP WITH ADAPTER FOR 69 Slant 6 to 64 904

Converter hub bushing/spacer

IIRC its about a .125 thinwall bushing with an OD of 1.806 (very close to larger crankshaft register) and an ID of <=1.560. Maybe make one out of a bunch of pieces of a 1/8 drill bit welded together. Its just a centering ring, there is no friction on it. If you run it without the bushing you'll crack your flexplate ears and possible run out your convertor bushing. Interesting find...these washers are 1.806 OD.....
Flat Washer - 1.344 ID, 1.806 OD, 0.004 Thick, Spring Steel - Hard

you could always change out the crank to an earlier pre 68 one....