Do NOT weld over the old frame number! In Cali, if you are putting a vehicle together that has never been registered or fell out of reg long ago, it needs to go to the Highway Patrol for a vin inspection. I can assure you that the Vin officer knows where the secondary vins are located and if it is welded over, expect the CHP to cut your frame up to determin the original frame number. Registration goes by frame number in CA. Much easier to leave the newer frame number and explain with paper work rather than explain why you have an altered(covered up) vin which is a felony. I have seen guys bring in restored vehicles only to find out that the secondary vin confirms vehicle is stollen. Then the new "owner" gets to remove what ever component he can prove that he payed for (reciept) from the stolen and the recovered vehicle goes back to the insurance company or previous owner. Obviously lots of lost time and money involved in that. There is a guy right now removing parts from a stolen Honda 250R three wheeler. We also just recovered a stolen 70 camaro that was stolen in the 80's!

Now if and when I do swap, I plan on keeping the 65 registered as a 65 and keeping the paperwork on the later frame handy if the issue ever comes up.