does anyone know what the stock valve spring installed height is? and how much lift they can take? and the outside and inner diameter?

 

All I know is max lift is around .490. Just low enough to preclude the safe use of 1.6RRs on the stock springs.

 

Installed height is 1.78. Max .485-.490 lift. Pretty much any mod will require at least the LT4 valvesprings, and those are good only to .525.


My suggestion: look at the Patriot Gold dual springs. With many aftermarket valves you'll need -.050 locks, but they include 10 degree locks, titanium retainers, seats, and springs good for up to .660 lift for $250 or so.

Shim and adjust installed height to desired seat and open pressure. Light seat pressure may require machining the spring seat area, especially if you need to use -.050 locks as I did to get enogh tip height for my self-aligning roller rockers.