Finishing a 365hp- Need Valve Spring Advice

[Greg Gore]

Hi everyone: We are putting the finishing touches on a 1964 365 and need some help with correctly setting up the valvetrain hardware. We have a Crane #967251 which is supposed to be a copy of the GM #3849346 cam. Can you advise about recommended valve springs; installed heights and what the seat pressure should be? The lobe lift is .322 and we are using the original 1.5 ratio rocker arms. Thanks, Greg

[JohnZ]

Greg, you want the GM #3911068 springs, still available from GM - 80# closed, 200# open at 1.25" installed height (Federal-Mogul #VS677 is the same spring).

O.D. - 1.239"
Free length - 2.027"
Wire diameter - 0.177"

Same spring was used on ALL small-blocks, regardless of the cam, from 307 grocery-getters to Z/28's with the "30-30" cam; that's the beauty of the Chevrolet factory performance cam designs - the flank profiles don't need heavy springs to manage the dynamics, and the soft action makes the system bulletproof.

[Greg Gore]

The local warehouse had the VS677's and they will be here this afternoon. Thanks much for the help!