FWIW, I just had a 4 inch lift installed on my 76' SBC 40. I looked at buying a kit vs. have my local spring shop do it and in the end am very happy with going with my spring shop. They custom built my spring pack, using new and reforged springs from my OEM stuff, and were even able to account for added weight (spare tire on drivers side, etc). When it was all said and done, they did it for 1400.00 including adding longer brake lines, bleeding, etc. without me having to lift a finger. I cant complain. I would recommend using a spring shop if that is an option in your area. Mine also was familar with FJ-40's and I have the added advantage of taking it back for readjustments in the future from spring adjustments, etc.
YC