71 gs 455 or 350

this may be common knowledge, but how can you tell if a 71 gs convertible came with the 350 or 455 originally from the factory. (? vin#)

 

Both were 434671...that year so you need the paper work which does not exist at Sloan or look for signs like the big or small block steering couple set up.

http://www.v8buick.com/showthread.php?t=31890&highlight=big+block+rag+joint

Rear gear is another indicia.

 

A good indication is the steering coupler. I think they are different.