501 rotary valve

[repairboy]

can anyone tell where i might find a "501" rotary valve for my 670 summit x, discontinued part and can't find anyone with one in stock.
Thanks

 

[winter brew]

Or you can trim yours to that timing spec.

 

[repairboy]

Or you can trim yours to that timing spec.

do you or someone you know have the specs to trim the valve to, any help would be great

 

[Turbotater]

cut it to 150/80.