Crate 225?

Shipping an engine is quite expensive.

When I lived near Mojave, CA I took my 69 slant to a big engine rebuilder in Chatsworth, CA and swapped for a rebuilt long block. That is an easy drive for you. That was 1994. They quickly removed the oil pan and crank bearings to insure a bearing hadn't spun before declaring my core usable. You could probably leave your block and return in a week if you don't want to do a swap. I expect you could provide a hotter camshaft for them to use. If you do swap, try to get one w/ a similar crank. 1968 was around the year they changed to a different register hole for the torque converter, and decide if you want a later hydraulic lifter engine.