Not necessarily. If you've upgraded to front disc, get 4 14 x 6 disc brake rims and you can be correct, and will be able to rotate your tires. Just be sure to get the trim rings that match your wheel; trims for 14 x 7 are deeper than trims for 14 x 6.
I cannot find anything that says that all F70-14 equipped cars came with 7" rims. It is possible that only V-8 cars were fitted with 7" rims, or perhaps just 400 equipped cars and HO cars...there is a lot of missing information here.
Parts index provides the following: JD 67-68 A, F 14 x 6 Rally 2 with DB JA, JT, KT 67-68 A, F 14 x 6 Rally 2 except DB KV, JO 68 Firebird 14 x 6 Rally 2 except DB KV, JO 69 Firebird 14 x 6 Rally 2 all KS 69 Firebird V-8 14 x 7 Rally 2
As usual, the numbers don't match or make sense. Why is one code listed as drum brake only one year, and disc brake the next? The parts index was written in 1973, and only the currently available replacement parts are listed. Many codes don't even appear here.
