I had a 307 in a 70 Chevelle Malibu. (4-door Chevelle) It was a smooth, easy-revving, durable and reliable motor, though not a very strong performer.
12437NOR10307 on body by fisher
124379N551058 on the dash vin
You will find the body condition to be of much more pratical value than the correct engine, down to original internals. Most of these “restos” get bought up by people with the means and the facility to bring them back to life, or sit in a garage so the cat has a place to have her kittens.
By the vin it shows that its a v8 with a standard interior says nothing about the size of the engine
And the cylinder bore is 3.985 or something close to that not a 4 tho
It was a rough guess with a tape measure…And it was across the cylinder in the middle
3 63/64" on your trusty tape measure but not defintely not 4" eh?
Thanks for the chuckle…
VIN’s never say any detail about the engine except the number of cylinders (8th digit). You would do good to find the build sheet, if you are lucky it is under the back seat, but no one is that lucky
EDIT: What I wrote is not quite true. The 8th digit of the VIN will give the manufactures one letter designation for a paticular engine. I can’t remember too many different letter designations except for the “X” engine. The X engine was the DOHC 3.4 that came in the Lumina and Monte Carlo of the late 90’s vintage. I remember the X engine in these cars as changing an alternator in an X engine Monte,or Lumina was in my opinion a terrible job.
Something is very fishy here. In the first VIN you gave: 12437NOR10307, The sixth character should be the last digit of the model year and therefor can not be a letter. Also the the seventh character appears to be the letter “O” No “O’s” or “I’s” were used they would have been either zeros or ones.
The first one is off the body by fisher tag on the firewall. The 2nd vin is off the dash of the car. I was asked to put both of them on sorry for the confusion.
The fact that you have 2 different VIN’s on a “matching number” car is somewhat disturbing. On the engine block there should be a machined surface that has the last five digits of the VIN stamped on it, if this differs from the VIN of the car the engine has been replaced. But it would appear that various pieces of this car have already been replaced. The first number you gave can not be the VIN for a 1969 for the reason I stated above. The second from the dash may have been a replacement dash.
I was told it was matching numbers but at the time I didn’t know much about cars I am 16 now and have been taking tons of classes. But thanks for all the help. I will double check the vin tomorrow and the O may have been a zero
I’ve run across this issue many times in restoring older Chevys. Most of the time, the older VINs didn’t tell you much. That’s the case here. If you want definitive information, go to the sites where the people who have these cars hang out. Here’s a great example of VIN decoding for your car- http://www.chevy-camaro.com/chevy-camaro-VIN-decode-first-gen.asp
The VIN tag won’t be as important as the body plate. Surely anything on that car can be decoded from that but gambling money says it’s a 350.
Another option is to consider it a non-matching numbers car which is near worthless and let me know where you live. I’ll be there PDQ with a thousand bucks and a towbar to relieve you of this devalued headache. Just pile the engine parts in the back. 
No thanks I got this car given to me in a will and I love it. The body has no rust at all the only thing that’s wrong is the engine just needs to be rebuilt.
I went to them web sites but tells me nothing more then I already knew. Thanks anyways