spring choice

ok so i bought a set of alum heads.
i was told my old springs were mopar performance set to match my
509* lift cam but there actually stock apparently and never got upgraded....
So will the 440 source springs be ok for this cam?...
I know that the advertised limit for these springs that come with the heads is 600 lift but is actually more along the lines of 550-560.
Im just not that familiar with cam/spring options and how important it is the be rite on and not under or over your lift.

I believe they'd be okay, but someone else would likely know better than I would, so here's a bump to move it up for ya'.

Mark.

hamesdart said:

ok so i bought a set of alum heads.
i was told my old springs were mopar performance set to match my
509* lift cam but there actually stock apparently and never got upgraded....
So will the 440 source springs be ok for this cam?...
I know that the advertised limit for these springs that come with the heads is 600 lift but is actually more along the lines of 550-560.
Im just not that familiar with cam/spring options and how important it is the be rite on and not under or over your lift.

Click to expand...

Spring pressures are determined by the cam manufacturer there's two numbers, open and closed.

Springs will set up differently at different installed hieghts, adding shims will increase the pressure. There is offset retainers and locks available to change spring pressures.

Just because a spring is good to 600 lift doesn't make it right for your .450 cam. The springs need to go on a spring tester and be set up to the reccommended pressures from the cam company..."Ready to Run Out-Of-The-Box" is a joke and if you believe that then be sure and buy 3-4 cams as you'll need them.

If you want to test the quality of a set of springs then check pressures O/C on everyone of them. The run the motor for awhile and remove one spring and check it, cheap azz springs will lose up to 20%, good springs will lose about 3-5%. There is no gains to be had in buying cheap reboxed imported springs, they're cheap go with good one's Comp, Crower, Isky are just a few that make very high quality springs that will last for years.

If the spring doesn't measure up it will allow the valve to float off the seat at RPM and the motor will just lay down.

Follow Cam Company's spec's to the letter.

Like was said... lift means little to nothing for what springs works with what cam. That being said, the Edelbrock springs are usually good enough to get around 320lbs open. It's not enough IMO to keep that .509 happy. Or perhaps the better way to say it is dual springs would be better. You can buy inner springs to make the Edelbrocks get much more, for a little bit more money. Have you machinist look into it. Also, the .509 is a good cam, but an old design and not really street friendly. If you are going thru the motions of replacing the heads, now might be a good time to replace that too and get springs to make your modern cam choice...