Hi guys im new here so over look me if i ask any already answered questions.
I have just bought a 71 mach 1 and i am pretty sure that it has the original motor
but is there a way to check for sure. I got really lucky i got the car at a really good price I have always wanted a mustang and was finaly able to swing it . Its a 351c
two-v c-6 auto any info would be greatly appricitated.

Thanks Jeff

 

the block may be stamped with the VIN on the back, near the starter. Ive heard conflicting reports on whether Ford *really* stamped *all* motors with the VIN after ~1968, so this may not be as definitive as you want.
________
Silver surfer

 

If you find a date code that is within 4 weeks of the body, it is likely the original engine.

Don't know about VINs on engines other than K codes.

With Mustangs, you'll find a very small crowd that cares about original engines. Original configuration is good enough for most concours types.