I'm looking at a 1966 T Bird to buy

My guess is that as long as the VIN on the ownership (title) matches the one on the body you are fine. It sounds like the rad support has been changed somewhere along the way, and that is not usual for a car of this age.

So, I'm guessing the number to go by is the one on the dash or on the door frame, right?

in my area thats a 20 + grander without issues like that, if nice cond.the under hood was the one important for registration as were none on dash,correct? had to been mollested, without at lleast 2 same could cause police scrutiny

Someone might have changed the door at one time because of rust problems or it might have been in an accident at one time and someone changed the door for a good used one and didn't bother changing the dataplate. If you have a title for the car and it matches any of the tags then you should be ok. I'm sure the two spots under the hood will match, just not on the door. You can get the VIN off the car in 2 places other then the door. On 1964,' 65 and '66 T-birds the VIN is stamped in 3 places total. One on the warranty plate that is located on the driver's door near the door latch. The other 2 places are under the hood and cowl. One on the right side of the cowl just under the windshield and the other just below that on the front of the firewall. Ford didn't put the VIN on the dashboard until 1968. I've enclosed a photo with the VIN places marked. If the door data plate VIN doesn't match the other 2, then the door has probably been replaced with another door from another T-Bird because of an accident and too much damage to the original door to repair so they replaced it with a used door from another car or it was too rusty to repair so it was replaced. This is a common practice in bodyshops with older cars as new doors aren't available from the dealer anymore so they get a used one from a junkyard. But the dataplate should have been kept and reattached to the new door if done by a shop. .It was probably done by an owner of the car and not a qualified repair shop. You can get an exact replacement door tag or commonly called a warranty data plate (which is quite legal and done all the time on restorations so don't worry) from Marti AutoWorks at http://www.martiauto.com/ for $28.00 with the new factory rivets. You give them the info and they make you an exact repro of your original tag. You should have no problems after that. If the 3 spots have different number then the car was pieced together and I would recommend stating clear of that car. Good Luck, Kenny/MrBlueOval

One more thing, The spot on the radiator cradle is probably the bad number if the frontend was wrecked and the cradle replaced just like if the door was wrecked. Check the alignment of the fenders against the hood and make sure everything lines up. There should be a 3/16 of an inch even gap between the fenders and the hood and it should be the same on both sides. Also check for overspray under the hood or newer looking parts near the grille and radiator area. If you find any evidence, then the car had damage and had frontend parts replaced. Replacement parts would not have the VIN stamped on them. Kenny/MrBlueOval

Match the title with the number on the firewall . The number on the door plate is the Warranty number and does not necessarily match the VIN Number , this is also true of the radiator support which should match the firewall number not necessarily the door plate , or may have been tampered with .