I have a chance to buy a set of 18x8 4.5 wheels cheap any idea if theyll fit on a stock supsension 68 running drums all around?

ttt

Without going through the "all these cars are a little different"..........thing the "ideal" backspace is 4.75" with a 8" wheel. If you like the wheels and they are a great deal that you can't pass up just run a smaller tire like a 235 instead of a 245. Another thought to consider is that large diameter wheels (18s) don't really look that great without the suspension being dropped a little.

In this thread the car has 17x8s with 4.5 backspace in the front with no issues. http://www.camaros.net/forums/showthread.php?t=151749

4.5" backsapce will be perfect.
Mine are with a 255-45-17 tire, I'll let ya know tomorrow if they are still perfect with a 275-40-17...

16x8 w. 4.5" BS on my '69 with no real issues. If anything, I could use a little more backspace since the outer edge of the tyres (245/50R16) come REALLY close to the rear of my wheelwells up front with the steering turned. This is most likely a result of the ~5 degrees of castor I'm running though. Worst-case you'd have to run 225's or maybe 235's up front, but I'd bet they'll fit OK.