I hate to beat a subject to death, but I'd rather be safe than sorry. Does any know if this combination will work? REAR-295/50 15 on a 15X10 5.5" BS wheel. FRONT-235/60 15 on a 15x8 4.5" BS wheel. I'm assuming the rear is correct width for a '68. Will be measuring it shortly. Any help would be appreciated.

Check this thread:

http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=8;t=002531

yes those will work do a search in this forum on my reg number 129 and you will see the different combos I have had on my 68. I am a tire and wheel fiend :D