North American P-51 Mustang (N51DL)

Does anyone know what model designation this is? The tip tanks are very unique.

I believe it's a -H, designed for high altitude ( the wheel strut cover is typical)

It is registered as a P-51D. Here is more info from Joe Baugher's web site:

44-13257 assigned to NACA Ames Aeronautical Laboratory, NAS Moffett Field, CA Mar 28, 1944 to Jun 2, 1944. Registered as NACA 108. Used for flying qualities, stability and control, and performance evaluations. Assigned to North American Aircraft, Inglewood, CA. Assigned to NACA Langley Memorial Aeronautical Laboratory, later as NACA Langley Research Center, Langley Field, VA Dec 22, 1944 to Jul 12, 1957. Registered as NACA 108. Sold on commercial market as N4222A in 1957. Remanufactured to Cavalier F-51D Mk II prototype in 1967. Sold to Lindsay Newspapers as as N51DL in 1972. Now owned by Lindair, Inc of Sarasota, FL and still flying.

Nice pic, Mark!

This is the prototype Cavalier Mustang modified from a late D model.
They installed the taller NACA tail and stripped out the fuselage tank and other military equipment. In its place were a second seat and plush interior mods and avionics. This one has the 110 gallon tip tanks.

These were built for the civilian market, Cavalier also rebuilt some F-51 D's for export to other countries for their military too.

Cavalier also built a Mustang with a Rolls Royce Dart turboprop called the Turbo Mustang III.
The project was sold to Piper and it was called the PA-48 Enforcer, the USAF bought two of these and they are now in museums.

The H model Mustang has much narrower gear doors, not like the D models and a taller fuselage and entrance to the belly scoop is changed too.

Thanks guys for the feedback -- I stand corrected and should have checked the registration.