I had a similar thread on thesmartclub forum where we explored suitable free wheeling pulleys for the petrol 450.
Due to constant abuse and negatively I never posted the final conclusion regarding suitable pulleys.
Both the petrol 450 and the 452 have M17x1.5 mm alternator shaft thread size and 57.5 mm diameter 4 grooved pulley.
There exists no suitable free wheeling pulley in that size.
The only solution is to source a pulley as near as possible to 57.5 mm in diameter and machine alternator shaft to suit. Alternatively, machine free wheeling pulley to suit alternator.