Mopar Action On-line – Tech Questions


Tech Question

Wesley Johnson,, Winnipeg, MB, Canada, 1981 Dodge D150 318

Rick, my truck is currently stock except for a 4bbl,dual exhaust, and a MP.430/.450, 260/268 cam. I am replacing the heads with a pair off of an E58360 that I had rebuilt. I am going to reuse the stock springs(I checked themfor squarness and they are all the same height) and I was wondering whatinstalled height I should set them at? I’ve read that you can go to within.100″ of coil bind and be safe, can I do that with these ones? Also what isthe correct free height of these springs so I can tell if they are sagged ornot. I don’t know if this is important or not but they use a triple groovelock. I know that I should use the matching springs but funds don’t allowthat right know.

Thanks and keep up the good work!


I’m goping to assume you mean the late-70s E-58. The earlier, ’76-down(Duster, etc.) version, used the same springs as 340s.

First, as you asked, here’s factory specs for the late E-58 springs:Pressure, valve on seat: 108-118 lbs (@1.66″)
Pressure, valve open: 186-200 lbs. (@1.25″)
Installed height: 1.625 – 1.688″
There’s no published free height specification. For good reason: pressurechecking is the right way to test a spring.

Installing any spring at less than the manufacturer’s recommended heightdimension is done at your peril. (OK, maybe 0.060″ less is safe.) Butthere’s more to the equation than simple coil bind! Without getting overlytechnical, I’ll just asnswer your question with a question: How do you knowthat you aren’t exceeding the wire’s limit of elasticity when you do this?Answer: You don’t!

These E-58 springs are about halfway between the old 340/360 hi-po springs,and the 360 2Bbl springs. Not really a bad choice. IF they were new. Valvesprings are cheap. And they are one of the most highly stressed, and mostoften fatigued, parts in an engine. Do yourself, your heart, and your enginea favor: Cut out 2 greasy burgers a week for a month. Take the extra cashand buy a set of new, decent springs.



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