Previously I posted info on prepping Vortec Heads
for use on the street. I recomended K-Motion K-700's
as and economical easy replacement for the stock L-31 springs
for moderate street/strip performance applications.
Well, turns out these are not such a good deal. In fact they are junk. Don't buy 'em. If you got 'em replace them. If you bought them on my recomendation, please accept my apology.
Don't like giving out bad advice.

Here is a list of stock diameter performance replacement springs
you can shop for to replace them.

GM pn#3927142, Isky #205D or 235D, Crane,99848,99846
Comp cams#981, Speedpro#V739R These are all good for .490"
lift when installed @1.70" installed height. You can reuse the stock vortec retainer and keeper. They are light weight and strong. All of the cam companies have online tech help
and are more than happy to help you select the right springs for your application.
For reference, these k-700's have a purple stripe that turns pink after use.

 

What went so wrong with the K-Motion's?

 

Well, they're considerably cheaper than comparible valvesprings from other brands. It's probably fairly impossible to make a proper hi-performance valvespring for $42.00.
My guess is, its a "get what you pay for" type scenario.
I jumped on them, and bought them because they were cheaper. I belive somebody on the TBI board also recommended them.
Then, the stories about them infallably breaking started to surface. It sounds like every person that's used them has experienced a breakage.
I'm returning them, and buying a quality part.

 

Here take a look at this. I don't think you will buy k-motion again.

https://www.thirdgen.org/techbb2/sho...hreadid=119021