I need a little help with BS, I have read everthing I could find on back spacing for front and rear. The first question I have is for the front I read that 4.75 is best with a 8" wheel, but is that with a drum or with disk? I have LS1 brakes and the disk is allmost a 1/4 thicker than the drums are, so should I go to 5" instead of the 4.75"? The second question is for the rear I read that for a 9.5 wheel to use 5.5" back spacing and I have a rear end out of a second gen 61" instead of 60" wide so I should go to 6" back spacing?
So this is what I think I can fit in
front 17X8 4.75 BS with 245/46-17
rear 17X9.5 6" BS with 275/40-17
Does this sound right?
This is a fully restored car with polly bushing and aluminum frame bushing so the front end should be thight.
Sorry for the long post but I need to be shure before I order wheels and tires.

WOW guys no comments on these sizes! Your making me nervous about ordering these. I sure would like to here from some one that has a 68 and this combination, Thanks

I have Vintage wheel works v40's on my 67. The front wheels are 17x8 inch with 4.75 bs. I have 235/45/17's on them with no rub anywhere. The rears are 17x9 inch with 5.0 bs. They have 255/55/17's on them. The reason i ran the 9.0 instead of the 9.5 was because i knew i was going to run the 255 tire. They have a good 3/4 inch on the inside of clearance and tons of room on the outside. Hope this helps you out.

Thanks for the info do you have disk brakes on front and rear? Do you think you could run a 245/45-17 on front with that wheel?

245's may be tight. I cannot say for sure if they will fit. I know VWW told me they would not. I have factory disc in the front and factory drum in the rear.

The front you should be good with the brakes you have and the 4.75 backspace. If the ride height is dropped 2 - 3 inches or more I would go with the 235 tire. In the rear if the 1" difference is from flange to flange (where the wheel pad sits against the axle) then yes 6" backspace - split the 1" difference. Keep in mind though as we always say all these cars are a little different so you have to check carefully and on both sides to make sure your combination will fit.