Will 245/60/R15 on 15x8, fit on a 66 LB fleetside?

[chrisrb2001]

Just got my 66 back on the English roads after 5 years.

I'm after 2 1/2" whitewalls for her and need a hand with tire sizes.
I have 15 x 8 smoothies with 4 1/2" back spacing.

I'm hoping to fit 215/75/R15 on the front (2 1/2" drop spindles) & 245/60/R15 on the rear (3 1/2" blocks), would this combo fit on with no messing about?

I would consider buying 15 x 7 smoothies, 4 1/4" BS if this would work better

Plus i've thought about 20" or 18" mobsteel wheels, but buying whitewalls in the UK for that tire size is a nightmare.

Cheers
Chris UK