Anyone know off hand what this might interchange with?

I ended up getting a Chevy v-8 and redrilled it.

It's a little frustrating that the vendors don't give much info on the pulleys they're selling. Mine is a double shiv 7" diameter pulley close to 3" in depth with a fairly close bolt pattern +/- 4 on 2". I can't imagine that the 153 had a unique pulley.

My 153 had the same pulleys as a 250.

I think I'm going to risk $30 on a used mercruiser pulley as they list the dimensions and they seem to match mine.