I know this has been asked before but I searched without finding an answer. I am Going to look at a 68 Road Runner project tomorrow. On '68 cars,Is part of the VIN stamped anywhere on the body, engine, or trans? I just want to make sure what I am looking at is a real Road Runner.

It might be stamped on rear of engine just forward of transmission mounting face, up on top behind intake manifold. All stamped numbers on body are not vin numbers in 68, as you have heard.

To be 100% certain you need a build sheet...
The VIN may be on the engine/trans but the engine/trans could have been swapped... So that proves nothing... The Fender Tag has the SO number same as the body... It will have the first few digits of the VIN but not the last six.. It will have the SO number so if the Fender Tag shows the RM designation & the SO number matches you know it started life as a Road Runner... Hopefully as the same Road Runner the VIN came on.

That helps, Thanks for the info!

SO # is stamped on the rad support upper yoke near the driver's side, and should match the SO # on the fender tag. There's another # under the trunk weatherstrip on the left side horizontal surface towards the rear.
Also look for 11" drum brakes, dual exhaust hanger brackets, holes for RR nameplates on the doors, trunklid & dash; might still have "F70" written on the underside of the trunklid. No console brackets, no extra holes for bucket seats. Coupe only until mid-model-year. RM21 (coupe) or RM23 (hardtop) VIN prefix.