DrX

iTrader: (6)

427 LSX pushing 20 psi, 9.0:1 static comp. Morel hydraulic roller lifters, Crower shaft mount rockers(steel, 1.8) Measured valve lift is .630/.640. ETP LS7/LSX heads were equiped with 150/420lb dual springs according to the build specs. Shifting at 6500 rpm. What kind of spring pressures should I be looking at for the rebuild?

TurboBuick6

iTrader: (2)

Is this going to be a drag race only car? How many RPM's will you be turning? Opps just saw 6500.

PAC's 1530 would be a good choice.

DrX

iTrader: (6)

Street and strip truck as per my sig vid . Shift is set at 6500 but it does hit 7000.

If I stay with the current lift, I think I may need to go to the 2.0 installed height as shown for the 1530s (current setup measures 1.8") - A bunch of my valve seals were totally destroyed. The increased open pressure may also help with that.

Wouldn't say my valvetrain is lightweight. PAC says that the small diameter of the 1530s is for lightweight valve trains - how does this relate to spring diameter? What retainers and seats do these use? catalog shows N/A

Any advantages re duals/singles?

Beau@SDPC

iTrader: (14)

Looks like something was not set up correctly really.

We have an entire package with the 1521 or you can step up to the Manley spring.
Either the 221435 or the 221436 would work for you. On those heads though, you should be able to run a larger spring. There are so many available that are over 1.3 OD.

Let me know and I can get you set up with a kit that will not leave you worrying. Both of those springs I quoted are close to what you had as far as pressures. The 221435 has some more seat and open pressure as well.

TurboBuick6

iTrader: (2)

I would deffinately go with duals as you are pushing 20 psi through the engine. We do have a titanium retainer for the spring. It is a mini 8 wieghing 10.4 grams (R532) the seat to match would be the S128. The 1530 was actually produced as a circle track endurance spring.

As far as the 1521 is concerend i am affraid it won't be enough spring for 20lbs of boost. They would work on the exhaust side but intake i would suggest more.

I would not be affraid of putting 200lbs on the seat at all with that setup.

DrX

iTrader: (6)

Definitley very little clearance(.020) on many of the seals at full lift. Not sure what the springs were doing either with the heavy valvetrain and 20 psi. No specs on the current springs other than the pressures. They are 1.5" diameter duals.

Beau@SDPC

iTrader: (14)

Who is WE? I have some guys running that much boost and more with the manley spring not having a problem. The Manley is what I would recommend and I have everything here ready to go. Or, Like I suggested, you can go with the larger dia spring like the 1.5 that is on there.

What ratio are those rockers?

TurboBuick6

iTrader: (2)

We is pac racing. I am not here trying to take your customers, I'd rather them go through you guys.

I am shocked that only 160lbs on the seat is controlling 20lbs. of boost.

DrX

iTrader: (6)

1.8 .

Beau@SDPC

iTrader: (14)

I bet a better set of springs are in order. Either the pac springs as mentioned like the 1530 or any of their larger OD offerings with the appropriate seats etc, or the manley set. We carry the Pac springs here (most of them) and can set them up quite a few ways. We also have the Manleys as well. There are so many choices, but spring pressure is in your favor.

Jason 98 TA

iTrader: (4)

Keeping in mind the PI/Mast valves are fairly long & heavy I agree a good spring upgrade is probably needed. There are lots of good spring options, but a call to Cary @ PI might be a good starting spot.

Brian Tooley Racing

iTrader: (13)

We use a K Motion K800, 200 seat, 500 open, on many boosted applications and their only $93.95 a set. TEA has the retainers and cups if you need them.

http://www.summitracing.com/parts/KMO-K-800/

DrX

iTrader: (6)

LOL.....Tough to keep up with who's who. ET > PIS > Mast

So bumping up the spring pressures to say 200/500 is the consensus? Better control without too much sacrifice in durability?

AES Racing

iTrader: (6)

Kmotion K-800, PSI CT1225, have used all in LS engines and worked well.

PAC 1371 would work well if you had 1.900" installed height

Beau@SDPC

iTrader: (14)

I would have thought that them being an LS7 style head that they would be a higher installed height than 1.8, but I could not find the info on ETs site.

AES Racing

iTrader: (6)

The valve for ET, MAST or LXR heads to maintain factory geometry, valve is 5.450", the tip length is .300". The installed height ends up being 1.770"(+/- depending on retainer etc). Suppose a +.100" valve would make it complicated with stock rocker, and really need an adjustable rocker.

Either that or use +.050" locks, +.050 retainer etc.

REV has something against moving the lock groove on the valve.

DrX

iTrader: (6)

Just checked my notes here. Looks like I wrote 1.86 installed height on the intakes which had .030 shims under the seats/locators. So exhaust would be 1.89. I might have the int/exhaust switched around though- I do recall measuring 1.82 somewhere- so it could be 1.83 int/1.86 exhaust.

Beau@SDPC

iTrader: (14)

Interesting indeed. Thats more what I though, but also changes what you will be looking for. Whatever you look for, just get something with a good pressure.

XtraCajunSS

iTrader: (2)

Been there, done that... The guys pointing you to the 190-200 seat and 500 open are right. You will need that minimum with those heads and that much boost, not to mention the added weight of the shaft mount rocker. I have always had to be very aggressive with seat pressures with Cary's heads due to the longer/larger valves, especially with 1.8 rockers. The Manley 221435's would work great. I've used them many times with great success although the PAC's and others mentioned are great springs as well.

Shane

TurboBuick6

iTrader: (2)

There ya go a 1.900 setup with the 1530's will put you right at 211lbs. with a .640 lift will put you about 570lbs on the nose.

keep in mind we can HS any spring to lower loads for a nominal fee. The spring rate will never change though.