Thanks for your effort:
I presume you are working on original Spencer receiver dimensions.
Certain reproductions vary visibly from originals.
Please identify your receiver(s) by model and any other important aspects such as caliber, modifications, etc. Many originals have been reworked and there have been reported receiver external dimensional variations as models arose.
These include documented differences involving receiver widths of up to approximately .125" and front to rear and top to bottom tapers. As far as I know, internal main dim's seem consistent, with minor differences related to extractor and ctg. cutoff variations.
There have been examples of original Spencers with upper block dimensional differences that allowed rimfire ctg cycling and firing, but would not allow modern standard dimension center fire conversion blocks without adding/ removing several thousandths of metal from the upper block face and rear surfaces.
Sporter receivers were sometimes thinner to reduce weight.
As Arizona Trooper posted: "One can find just about anything on a Spencer."
I do not know of CAD animated files for Spencer's. I have seen them for lever action/falling block action rifles that included animation of parts relationships and interferences detection.
Somewhere in this Forum are posts with perhaps AUTOCAD color line drawings of various mechanical aspects related to cycling issues.
All the best,
El Supremo/Kevin Tinny