KillerCrate Matched Valve Springs FAQ

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KillerCrate Matched Valve Springs FAQ

SOME NEW SPRINGS SUCK
Just because springs are new in a GM box - doesn’t mean they are good. To build a set of Matched Valve Springs,
KillerCrate takes several boxes of Genuine GM Performance Valve Springs and rate each one. GM Specs on 80lb springs are
plus (+) or (-) minus 4 lbs, which means in a standard GM box, you may get some 76lb springs and some 84lb
springs. In reality, going through GM sets – we see some stock springs in the low 70’s.
KillerCrate selects matching springs over 80lbs, group the matching ones together and then they get boxed as a set. The
lower pressure springs get tossed in the garbage can or sold to Street Stock guys.
WHY WOULD MATCHED SPRINGS BE BETTER?
In addition to getting higher pressure springs, Matched Springs have more consistent valve control than
unmatched. The matched springs help in continuing the power output past the peak hp rpm by controlling the
lifter plunger for more consistent valve motion. Think – a rowing team in a boat – all rowing at the same time with
the same strength. Matched springs are ready to run right out of the box and do not require break-in.
HOW LONG DO THEY LAST?
How long should you run springs depends on the length of your track and the RPM range. Springs will last longer
on a 3/8 mile track with a 6000 chip than a long 5/8 mile track where the engines run 6400 RPM. On average, you’ll
see fall off between 300-400 laps or 5 race nights for a set of 80’s, which is when we would recommend that you
should replace your Valve Springs. If you test them and you are around or under 75lbs then I recommend it is time
to change them.
On a 1⁄2 mile track with a 6200 chip, here is a good rule of thumb before fall-off.
80 = 5-6 Races
81 = 6-7 Races
82 = 7-8 Races
83 = 8-9 Races
84 = 11 Races
85 = 13 Races
If you are really hardcore - you can check the Valve Springs using an on-head tester right after you install. NOTE
ALL SPRING BUCKETS vary on engines so use our number vs you're on-head number to set your own baseline.
Re-measure and record in a notebook your worst spring reading every 2 weeks with an LSM Valve Spring Tester
(PC-100/160); watching for the fall-off point around 74-75lbs. Then it's time to change the Springs and by watching
the readings you will know when to change your springs without guessing or using a rule of thumb. For Dirt
Sportsman Modified Applications, where the roll cage is in the way, we use the LSM slant handle adapter for
clearance with the on-head tester.