GM hydroboost pushrod length

[brownge]

I'm putting a GM Hydroboost from an early 90's Astro van and a new Wilwood master cylinder (model 260-8556-P) on my '72. I bought the hydroboost from O'Reillys but it didn't come with the pushrod, spring, and retainer. Another member helped me find a site (http://www.tallonhydraulics.com/stor...ex&cPath=40_16) that sells these items but I need to know the pushrod length to order.

Do any of you have the same setup and could help with the correct pushrod length?

Thanks!