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PAC or Manley valve springs

17K views 40 replies 17 participants last post by  WeDgiE 
#1 ·
Deciding on a set of PAC 1224 or Manley 221424-16 valve springs. Which set?
 
#3 ·
Bullet .800 lift solid roller with 1.8 rocker ratio for Ls na motor. I was told to run at least 250/750 spring pressures and 275/800 was optimum. I found a lot of choices in retainers for either spring because I need .100 tall retainer to bring up the install height up.
 
#6 ·
what dia.?
 
#7 ·
the 1224 spring says its 306lbs@1.950. im a dealer. in their book, they list their spring pressures at .050" increments.

if you can get a true 2" installed height, I would run the #1228.

PSI has a spring might work
 
#11 ·
I just freshened up a set of heads with the 221424 and after 200 passes on .800 lift cam they were all within 10psi. that was set up at 2.000 and had 275/775# and really didn't lose any pressure. Course that was turning less than 8k. If you are doing a heads up deal turning over 8500 I'd probably opt for the PAC springs with their extra treatments. And then note like in a similar post on here that even though the pressure may decline, the springs may still break from fatigue so keep an eye on them
 
#18 ·
Yes, i'm a PSI fan.
 
#33 ·
Yes. 800. Put them in at the same time I went to Jesel 937 keyed lifters, and between the 2 things, I eliminated valve train problems. 2007-2012 on the same springs, Couldn't be happier. If all goes well I should be replacing the current set of springs in the summer of 2017 lol
 
#37 ·
Can't go wrong with any of the 3 really. PSI, PAC or Manley.... all good spring choices.

But I am heavily partial to PSI because 1. Their quality is awesome... if you measure their springs(wire dia) and coil bind dimensions you really get spoiled by the consistency.... it don't fluctuate from the stated specs much if any... 2 . They are just down the street from me and support my local town with employment and taxes, and 3. the people who run that deal are super down to earth, genuine nice people... just an awesome company from what I have seen.

You know that PSI feeds their people? They have a whole lunch room and have supported their people with snacks and food since they started(from what I've been told there)... My kid delivers UPS there and he says they feed him LOL.
 
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