XB Roller rockers?

[christianmb]

Since there are many whom are more knowledgeable than I, and I pose a question to you. I am thinking about putting 12:1 pistons in the XB "Valerie" over the winter. What other upgrades should I look for while I'm in there? I'm already planning on a Cometic .030 gasket kit. Here is what I'm thinking about:

1.725 ratio roller rockers
stronger valve springs for higher RPM
...???

If I do the rockers (or any roller rockers) I have seen that I need adjustable pushrods with either the 1.675 (stock) or 1.725 ratios. Why is that? Why can't I run stock pushrods? I'm trying to reduce friction in the top end and gain a little more power and reliability out of the top end while possibly pushing the RPM limit to 7000 or so.

Any and ALL advice is welcomed...thank you!

 

[EricZ]

You will need adjustable pushrods (or measure what length you need and get a custom length solid set) because the new rocker arms slightly change the rocker arm geometry and can change the lifter preload beyond it's useable range.

Stock valve springs will easily handle 7500rpm-- that's the factory redline on XB9s.

 

[christianmb]

Cool! Thank you for the help EricZ. I wasn't sure since the 12's are limited to 6850 factory (or at least mine was).

Any other inputs as far as other mods?