Carburetor jet sizes...

If it’s still knocking (even only on a slope at 90mph) I would back the timing a tiny bit just to be safe. Going uphill at 90mph probably means your vacuum will be very low and leads me to believe your mechanical advance is a tad too high.
Just a small sidenote, but a fuel starvation problem (lean mixture) can also produce knock.

Thanks. A couple weeks ago, we’d opened up the jets and the carb is running rich now. That helped a lot.
I definitely think the distributor is wonky.

Would like to get a new one. Preferably one where we can easily change/adjust the curve.

CJ Pony Parts has a brand new Drake HEI small block distributor on sale right now for about $90.

Randy Goodling
CCOA #95