Did this to a 6" Starwatcher with some success:-
http://www.iceinspace.com.au/forum/s...ad.php?t=59447
In November will fit better and more stable long bolt mount options - I think it will work fine.
Your 8" mirror and cell will be heavier, but your replacement bolts will probably be thicker.
Just check that you can still see most, if not all, of your primary in the Secondary. You shouldn't lose much.