Please help with the value of my truck

[ratrod67]

I just had my insurance cancelled because they don't agree with the value I have set on my truck. I've had the insurance through State Farm for about 3 months now. When they asked for the value I said about $6000 and they agreed to sign the policy. Now they say upon further review they are dropping coverage down to $3200. My next step is to have it appraised but I just wanted to make sure I'm not being crazy with the dollar amount. Here are the highlights and a few pics. Please help me figure if I should pay the $125 for the appraisal or just leave the value they set. Thanks!!

67 SWB straight body with minor dents(notheing big mostly door dings)
99% rust free. Just some surface rust and 2 pinholes in the driver cab corner.
Has a 69 bed and doors. The following parts are new: Windshield, gaskets and weatherstripping, bumper, all lights and lenses, tail light harness, blazer tank, front sway bar, grille loops.
Has a new 383 stroker with forged crank, 2.02 heads, comp cams valvetrain and cam, Edelbrock intake and carb, new exhaust system, fresh 350 tranny with new stall and shift kit, Fresh 3.73 rear 12 bolt, all front suspension is new(everything) swapped to 5 lug all around and disc in front., power steering with new pump and lines, new carpet, seat recovered, dash cluster, B+M shifter, door panels, armrests and lots of little stuff( dash knobs, interior light, window cranks, ect)