Yes, the cut off year for NSRA is 48. It is actually 1948 and back. Cutoff for Goodguys is 1972. By the way, NSRA is changing either two or three of it's events this year to 1972 cutoff dates!!
I have a 1937 Chevrolet 1/2 ton pickup and the "VIN" on the title is the number that was on the original engine - two engines ago. The truck was also one truck made from two different trucks. I have pictures of both trucks, but I couldn't tell you which truck is my truck. I just know it's one of 'em.
As far as I'm concerned, I have a title and I have a truck and THEY are registered together. Period! Unless I start something on it, I don't really see that it is an issue.
My stand would be to let that BIG OLE DOG SLEEP!!!!!