How can I find out about this?

[RROriginals]

Well, I have a 1973 Plymouth Roadrunner sitting in the driveway,
One problem: The first owner (I'm the third) took the fender tag.

Mine has the VIN: RM21P3A-----
The VIN states it has a 400 BB V8

But my engine block and transmission are a pair and haven't been swapped out,
it's a 440 Engine paired with a 727 TF Auto trans

I also have a sunroof, I KNOW that some Roadrunners came stock with them in the '73 era.
These are the production numbers made:

440-4 GTX: 749
Auto: 749
Sunroof: 414

Any way that I can determine if the Sunroof I have is factory or aftermarket?
Also why is my VIN telling me a 400 block, but it's a 440, matching trans.

I've had it looked over and numerous shops and fanatics of the Birds tell me that it's never seen a swap.

[41husk]

How can they tell  it has never been swaped?  When I bought my 70 Challenger i was told it had the original 318/904.  Several years later when I pulled the block it had a 73 dated 318.  Now thats a cool trick until then I had alway thought it was original.

[tan top]

hello & welcome !!  , sounds interesting !!     can you  post pictures of fender tag &  the vin stamped on block & transmision  & of car 

[RROriginals]

I've looked at all the castings, unable to get pictures at the moment but when I do I'll post them.

To Tan top: I stated the tag was taken from the car.

I've done my research, the block is the correct period, '73 block in my '73 car, with the pairing tranny.
Even if it ISN'T Original, still better with a 440 

[tan top]

I've looked at all the castings, unable to get pictures at the moment but when I do I'll post them.

To Tan top: I stated the tag was taken from the car.

I've done my research, the block is the correct period, '73 block in my '73 car, with the pairing tranny.
Even if it ISN'T Original, still better with a 440  

opps sorry dude , i miss read you post    

have you checked for a broad cast sheet  ,

[RROriginals]

It's no problem.
Here's some pics for 'shiggles'.

[Alaskan_TA]

Have you compared the partial VINs on the block & transmission to the car VIN yet?

Have you checked the body numbers yet?

[RROriginals]

All I'm really interested in is the sunroof. I have multiple people tell me it's aftermarket.
It'll just clear my head if I find out, then maybe put a little 'oomph' on my car, if it's stock ofcourse.

[UFO]

So the fender tag is gone,how about a broadcast sheet like tantop mentioned?
A manual opening one is optional.Without some type of paperwork it could have been installed by a previous owner.

[RallyeMike]

Is the sunroof made of metal and rolls back into the roof? Then it is stock. Otherwise, it appears to be aftermarket (from what I can tell by the photo).

Mike

[RROriginals]

Aftermarket then. What a shame, but ohwell.
Still wonderting why it has a 440 instead of a 400, but I know the engine wasn't swapped over.

[RallyeMike]

Still wonderting why it has a 440 instead of a 400, but I know the engine wasn't swapped over.

You can put the wondering to rest with a little effort:

If the car has the original engine, the same # VIN on your dash is stamped on a pad on the side of the block by the oil pan. Dive under, wipe it off and see if it matches. If the numbers do match, and the engine is actually a 440.... your car is a mis-stamped VIN 1 in a million.

[RROriginals]

Doubt a Mis-stamped VIN would increase the price. Lol but atleast I'll know.

[maxwellwedge]

Of course it was swapped - Check the engine and tran VIN's.

[no318]

The other possiblity is that it IS a 400 and not a 440.  They do look pretty similar if you aren't sure what you are looking for.  I agree that getting the #'s is the answer. 

If it is a factory sunroof, it will be solid, body color, and manually slide back into the roof with a crank.  If it is glass, or raises in the rear, or slides, or is power, it is not a factory unit.  I would think it pretty unlikely (not unheard of) to install a factory one into another car.