Mary Shelley's Doctor Frankenstein was forced to make his creation larger than a normal man in order to be able to surgically reassemble the body parts he obtained by robbing local cemeteries. How was Victor Frankenstein able to get enough plus size body parts to make his 8 ft 2 in monster when the graveyards were likely full of average size dead people?
The book doesn't make it clear exactly how Frankenstein created his being. Decades of films have left us with the impression that it was built from whole parts, a leg here, and arm there, and presumably whole organs, but if anything the book suggests the creature was built from smaller bits. For example Frankenstain says:
I collected bones from charnel-houses and disturbed, with profane fingers, the tremendous secrets of the human frame.
If he was starting with bones presumably he wasn't just stitching together whole body parts, and in that case he could have constructed limbs any size he wanted. There's also the statement:
The dissecting room and the slaughter-house furnished many of my materials
where the mention of the slaughterhouse suggests that maybe not all the parts came from human bodies.
Shelley does not explain how Frankenstein managed this; only some passing comment that he chose the size to make working with minute parts that much easier (which we now know makes absolutely no sense).
The closest explanation I've heard is, in all places, in YOUNG FRANKENSTEIN, where Froederick is reading the journal and something is said about artificially increasing the size of the body parts. Again, it makes no sense.