Replace the default line in vehicles.ide:
579, huntley, huntley, car, HUNTLEY, HUNTLEY, null, richfamily, 6, 7, 0, -1, 0.90, 0.90, 0

Replace the default line in carmods.dat:
huntley, bnt_b_sc_l, bnt_b_sc_m, bntl_b_ov, exh_b_l, exh_b_t, nto_b_s, nto_b_l, nto_b_tw, rf_b_sc_r, spl_b_bbr_m, wg_l_b_ssk

Replace in handling.cfg:
HUNTLEY 2500.0 6000.0 1.5 0.0 0.0 -0.40 80 0.73 0.96 0.51 5 210.0 55.0 180.0 4 P 7.1 0.48 0 31.0 0.53 0.11 0.0 0.1 -0.175 0.436 0.2 0.2 0.35 40000 00442020 00404404 0 1 0

Add in car4 section of carcols.dat, also remove the default huntley line from car section:
huntley, 32,25,36,24, 0,0,36,24, 90,90,36,24, 96,96,36,24, 75,75,36,24, 125,125,36,24, 40,0,36,24, 34,34,36,24