if the compression numbers are in the norm (~130-150 ish) then that says that the long block is OK (no blown head gasket or slipped tchain). dist housing was unmoved. its getting multiple sparks at the plug wire plug ends when cranking correct?. new gas. I keep coming back to vac leak. I would do What Andrewh said (1) do some vac leak diagnostic checks & (2) then borrow another carb. EDIT but the having to floor it goes against the vac leak idea. When it starts can you look in the carb (carefully) & see if it is dripping. Keep us posted!