71CamaroLS1

I just installed Pat Gold Extremes, along with a 227/235 .614/.621 cam, in my LS3 crate motor. It's running without issues in the early miles, but I just read on Corvette Forum (SpinMonster) that the Gold Extreme package actually installs at 1.74 installed height rather than the specified 1.80, and the max lift as installed is therefore .600 rather than .660. Can anyone else confirm/deny this data?

I'd rather not have to try to borrow a valve spring mic and pull a couple of springs to check, but I would way rather not have another motor blow up!

BTW, Patriot themselves say that the springs install almost exactly at 1.800 on factory heads.

TVWilkes

That is true to a degree. The installed height needs to be in the 1.800 range to get anywhere neer .660 lift. If installed at 1.800 it will have plenty of spring pressure to run your cam. I would think the package would setup at 1.800 (as shipped from Patriot) and you would have to use shims to get it to 1.740. If the package is installed at 1.74 it will have more pressure than you need and only be good for .600 lift.

71CamaroLS1

Yes, if you shim the springs you lose max lift. But what I was reading is that the Gold Extremes install at 1.74 with just the provided hardened seats - and obviously, you can't unshim them from there back to 1.80

I've decided not to worry about it for now, the Patriot tech person sounded quite confident.

vettenuts

iTrader: (4)

Stock springs aren't at 1.8 either. 1.8 is only a part of the spring specification. You really should mic them, so much depends on them being correct.

Gh0st

iTrader: (3)

Why would they advertise them as 660 lift if you're saying they' only do 600 lift ?

racer7088

Those springs do setup around 1.800 or so with their locators etc. on a stock LS1 head but you could shim them up a little if you had less lift and wanted to turn higher rpm a lot. Like TVWilkes said though they already have decent pressure at 1.800 but without setting them up yourself with a real spring mic you will never know what they are at. I know on a dead stock OEM head they are indeed at about 1.800 though.

NEGEN@SDPC

iTrader: (9)

Ok here ya go hope this will help you...Those springs are to be setup at these specs to achieve the .660 lift....
155lbs @ 1.800 closed
410lbs @ 1.140 open
1.090 is your coil bind

71CamaroLS1

Thanks Erik, that's what I needed to know. They have more than enough spring pressure at 1.800 for my application, but I was worried they would install well short of 1.800 and thus I would exceed max lift recommendation.

Hotrod406

iTrader: (6)

Mine installed at 1.750. The heads are L92 with stock valves. My cam is .610 so I left the springs at 1.750. No problems in 5000 miles but it is annoying that they didn't come out at the advertised height.

Jim85IROC

iTrader: (6)

I keep measuring mine between 1.735 and 1.75, depending on my measurement method. I obviously need a more accurate way to measure these heights, but no matter how I do it, I'm WAY under, and now I'm looking for different springs as a result.