Is there a block lift kit that will fit a 69 Barracuda

AJ/FormS said
The largest tires that fit in a 69 Barracuda are 325/50-15s on 10inch rims.
Second largest are 295/50-15s also on 10s.
The standard backspace on those is 4.5 inches.
To install those. you will have to move the spring inboard to at least flush with the inner wheelwells.
Then you will need to narrow your rearend to move the wheels to that inner well surface less 3/8 inch per side, to allow for body sway in the turns.
Then you will still need to roll up the outter knife-edges vertical to prevent the tires being cut.
To prevent you having to narrow the rearend, you can increase the backspace to about 6 inches, but for 295s you will still have to move the springs.
My conclusion is twofold;
1) you are not trying to fit the largest tires that will fit, and
2) you got the wrong backspace wheels.

You're right, not the largest, the largest that would fit without requiring other modifications. (op updated)

AJ/FormS said
Your cheapest, and best solution therefore is to just get the right backspace wheels.

I think we went with the deepest backspace which they could get in those wheels.
The wheels are 15/8 (would have liked /10 but any larger rubbed without hitting bumps)

My invoice says "15x8 5-101.6" I'm not sure if that tells us backspacing info or if that second bit is SBP?

Tires say "255 /60 R15 102S SL RWL" Not sure what the numbers after the 255/60 mean.

AJ/FormS said
But remember this;
do learn to drive it differently before you go testing the cornering limits.
And ; the brakes don't work when you are sliding sideways; you are gonna have to ride it out. So leave yourself some run-off room,lol.

Roflcopter