Valve Springs

[Allan J. Wicklund]

Having experienced a little bit of valve float on our 67 w/350HP 327 at around 5200 RPM I'm anticipating new valve springs. Any suggestions? Thanks, Al W.

[Joe L.]

Re: Valve Springs

Allan------

The "trick" with valve springs for a street engine is selecting a spring that will have spring pressure which works at the maximum RPM for your engine and, at the same time, not more spring pressure than you need. With valve springs, more than you need is not better and it's not without a "downside". Mostly, the "downside" to excessive spring pressure is greater camshaft wear.

For your engine, my recommendation would be the stock valve springs which were originally used on it and are still available from GM. These are GM #3911068.

For applications in which a hydraulic roller camshaft is retrofitted to an pre-1986 small block, I recommend GM #10134358. These springs can also be used with flat tappet cams, but you'll slightly increase camshaft wear and you likely won't get any performance benfit out of them.

[Duke W.]

Re: Valve Springs

Assuming the engine still has the L-79 cam, the 068 springs should allow the engine to spin to at least 6000. With OE mechanical lifter cams, these springs will allow the valvetrain to go to about 7200.

If the engine is "laying down" at 5200 you may have another problem.

Duke

[Verle R.]

Re: Valve Springs

Allan,

Are you sure you are getting valve float?
Ignition breakdown could also cause the engine to stop pulling and sound bad.
Check the fuel pump and carburetor also.

Try the simple things first before you go to the hard/expensive fixes.

I would look at ignition components first.

Verle

[Allan J. Wicklund]

Re: Valve Springs

As usual, good advice all around. Thank you gentlemen! The whole story is as follows. Just finished rebuilding the correct "Date" coded engine for our car. New block, old heads but heads are very low mileage having been done in 1985 and car stored until 1998. My intentions are to break in the new camshaft with out touching anything except adjustments. If performance issues need to be addressed I'l start checking components for wear or failure. Thank You for present comments and future comments. Al W.