Looking for recommendations valve spring for a LA with either the .557 or .590 solid purple shaft.
Last engine I built was a 440 with a 590 cam probably 10 years ago everyone was saying k-motion were the way is that still case

for the .557 cam the mopar spring recommended is P3412068 https://www.manciniracing.com/mopupto620li.html but depending on your valves you might need something different.

On my iron heads I have .100" longer valves so the installed hgt. is more, we went with a Pac spring ( I think 1208, have to ck my notes)and retainers to achieve similar specs to the 068 spring.

What lifters? On the .557 on a small block I use comp 977-16 on beck style lifters set to near CB and if it still made power at 7600 id shift there.

I have used a K motion spring on a set of heads that I needed a spring for a if I recall a 1.900 installed height, it was on the lower end of there offerings id have to look.

as for lifters i plan to run what comes with the cam as long as there is not something im unaware of better to run i ordered the mopar 3412068 today next choice is the 590 or the 557 i like the 590 profile in my 440 i advanced it a bit when i degreed it in to help the lower end and it still pulls good up high some im leaning towardsit

Basically....... the available spring installed height determines the “group” of spring you’ll be looking at.

Stock SB heads utilizing stock style multi-groove valves end up with a pretty short installed height(1.650”-1.700”)...... and they’re aren’t many choices suitable for the 590 cam with that combo of parts.

Ede heads are a nominal 1.800”........TF heads can be 2.00” with their Ti retainers.

You wouldn’t normally use the same spring for the same cam with those 3 different heads.