Butler says the Northwind is 1.25 inches shorter than a Victor:
https://butlerperformance.com/i-3000...tegory:1291427
Summit says a Victor is 7.7 inches:
https://www.summitracing.com/parts/e...7/make/pontiac
And an RPM is 7.45 inches:
https://www.summitracing.com/parts/e...6/make/pontiac
So a Northwind should be about 7.7 - 1.25 == 6.45 inches. If you can use an RPM without a spacer, you should be able to use a Northwind with one.