Well, the first digit will be a "J" for shure. (Challenger). The second digit will be "H" or "S". Here is my suggestion. Determine what is your engine.
6 cyl=C, 318=G, 340=H, 383-2=L, 383HP=N, 440-4=U, 440-6=V and Hemi=R. Now, knowing that the smallest engine available in a Challenger R/T
was a 383HP, if your engine is a 318, you'll know that your second digit will be ''H'', (non R/T). On the other end, if the engine is a 440, that means you
have an R/T, so the second digit will be ''S" (JH=Non R/T, JS=R/T). But that's assuming the sequential number on the engine is BO 265408, (your
sequantial number on the shell).The third digit (number of doors) will be "2" for shure, and the fourth digit will be "3" for hardtop OR "7" for convertible.
Sixth digit will be "0" (1970 model year) and we know your plant code, (seventh digit) is "B". Tell me what is the engine and if it matches the sequential
number on the shell. The sequantial number on the engine can be found on the passenger side of the block, at the very bottom, along the oil pan,
about half way. If it matches the sequential number on the shell, you will be able to determine the beginning of the VIN. If the sequence on the block
doesn't match the one on the shell, I' d say you' re in trouble. For exemple, let' s say you have determine the sequantial number on the block matches
the one on the shell, and you have also determine that your engine is a Hemi, your vin would read as JS23R0B265408. (assuming it' s a hardtop). It
woulb be JS27R0B265408 if it' s a convertible. If its a 318, 340 or 383-2 bbl, that means the car isn't a R/T and the VIN will begin with JH23 (or 27).
One more thing. Small blocks have usually the cubic inch stamps on the driver side of the block with large number, while 383s have a machined surface
below the distributor where it will read 383 or 383HP. 440s have a machine surface on front of the block, between the the intake manifold and water pump
where it should have the number 440HP stamped. If it is a six pack, it will only reaf 440HP, not sure how to determine if it's a 6 pack or not, (a six pack
manifold might have been add on a 440-4 engine). Also, there were a small amout of non R/T cars that came with a 383HP. So if you have a
383 or 440, it might get a bit tricky, but if you have a 318, that should be easy to clear that up, again, assuming the sequantial number on the block matches the one on the shelle If you have more questions, feel
free to ask and if I can help, I' ll be happy to do so. Have a nice day. Robert