tecumseh hk, hsk difference

[jake22si 5]

Is there much of a difference in these engines, I have a 7hp hk ariens 910008 snowblower and am trying to put an engine off a st724 hsk. I have to change the pulley but the newer engine looks like it has a bigger shaft. When I look up the specs it says they are the same size?

[jake22si 5]

just pulled the pulley out to match so all set