This is the site someone posted earlier.  It contains lots of good info.
I was particularly interested in the temps mentioned; i.e., con rod
bearings: 200-375, main bearings: 200-350, top ring: 300-650, and
combustion chamber 3000-5000!  The max operating temp of dino oils is
given as 400, and synthetics as 500.

http://www.vtr.org/maintain/lubricants-redline.html
--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Driven since 1969)
'74 MGB GT (Restoring)

Assisting on Restoration:
'72 MGB GT (Daughter's)
'64 MGB (Son's)

Parts cars:
'68 & '73 MGB, '67 MGB GT