Removing the lower radiator hose only drains the water pump, whose connection
with the water jacket is at the head/block interface so you cannot drain the
block by simply disconnecting the lower radiator hose.

Many later blocks (maybe all of them, but I'm not sure) have about a 1 1/4"
hole about an inch deep roughly 4" below the connection to the thermal timer.
(The thermal timer screws into a boss which has a UNC BOLT thread and does
not connect to the water jacket. It is handy for lifting the engine, however.)

The recessed hole lower in the block works well for a block drain if you can
get the plug out. One thing I always do when I have a block out is to remove
the plug (1/4" NPT with a 1/4" square socket in it). Normally you cannot
just unscrew the plug and get it out. I have (carefully) drilled through
several and found that this is one place where the so-called "Easy-Out"
actually works. After you take this plug out you can install a 1/4" NPT
drain cock.

Following is a link to the "Lola" website. In the second picture you can
see the two holes in the rearward right side of the block. The upper one
is the Thermal Timer boss, the lower one is where the drain hole is located.
http://www.super-crush.com/gallery/lola
(Many thanks for the FINE illustrative pic!)

Without the block drain cock, you need about 4 feet of 1/4" OD plastic tubing.
After draining through the lower radiator hose, remove the water outlet and
thermostat from the head. You'll see some coolant down there. Feel around
with the end of the hose until you find where the water passage goes through
the headgasket. With that in mind, fill the plastic tube with water and close
one end with your finger. (Having a helper do this is good.) Then put the
open end down through the water passage to the bottom of the water jacket,
lower the closed end to a bucket on the floor and siphon nearly all the coolant
out of the water jacket. There will probably be some left but not much.
--
George Downs, Bartlesville, Oklahoma, Central US