Kinfolk

I have a 2002 LM7 5.3 with all supporting mods I'm installing a TSP stage 2 cam in. Specs are 212/218, .550/.550, 112. I was wondering what would be the appropriate sized beehive valve spring to avoid high RPM valve float while also avoiding HP loss through stiff valve train. Would it be better to get a set of .550 springs or some .560 springs?

TurboBuick6

iTrader: (2)

PAC-1218, they are drop in.

Kinfolk

Those are .600 lift non beehive springs right?

shakenfake

Why not just get some LS6 valve springs? I have them with the same cam in my LQ4. 15k miles no issues and they were used when I installed them, low mileage though.

TurboBuick6

iTrader: (2)

Direct fit drop in beehive

grinder11

iTrader: (1)

My opinion, but I'd run PAC springs over the LS6 springs any day.

Kinfolk

Thats what i’ve been leaning towards, are you running the GM performance .560s?

Kinfolk

The closest lift rate i can find from PAC is .600. I feel like i would loose HP from the valve train being to stiff.

Che70velle

iTrader: (6)

TurboBuick6 works for PAC tech department. You can trust what he says.

Kinfolk

Not doubting anyone, just wondering if they have the most ideal lift rate for a .550/.550 cam. Does anyone know if they sell a kit with the retainers and keepers?

MuhThugga

Being a drop-in, the 1218 uses your stock retainers and keepers.

However, you could just use a set of factory LS3 valve springs being at .550 lift, provided that you are using factory rockers. TSP's description of that cam even says that it is designed to use factory LS6/LS3 valve springs.

shakenfake

^^^This guy *****. You spend a third of the cost to get an OEM spring that was designed for the average consumer. I wouldn't think twice about buying them over any other valve spring in this scenario.

https://www.summitracing.com/parts/nal-12499224
These are them, they say .570 lift on here.

grinder11

iTrader: (1)

If you like running a spring to within .010" of max lift, by all means, go for it! PAC makes springs as good as, or better than, anyone. I have some 1905 duals in an LS7 engine. Been in there for 39,000 miles/8 years. You get what you pay for. YMMV....

shakenfake

I mean it’s within .010” on the stock Z06 cam too but go off I guess.

99 Black Bird T/A

iTrader: (4)

Been in the LS game since 1999, PAC has always had an outstanding reputation. Folks literally jumped for joy when PAC started offering springs tailored for LS applications back in the day.

Saw enough brand new stock LS1's have valve float at the end of the dyno runs back in the day to always spend a little more for high quality valve spring like PAC.

YMMV

grinder11

iTrader: (1)

You can lead 'em to water, but......

MuhThugga

The lift rating is not the same as coil bind. Running a spring to it's max lift rating isn't a bad thing, because that means the spring is being used to about .050" from coil bind. While a beehive is much less susceptible to harmonics, running traditional springs further from coil bind can result in bad harmonics and valve control, and lost power as a result. Just like too much spring will lose power.
This is why I run a .630 spring with my .629 lift. It doesn't make much sense to run a .660 spring because I am just unnecessarily further from coil bicoi

grinder11

iTrader: (1)

I agree it is usually OK to do so, but there are more ways than one to skin the cats ***! I should have elaborated a bit more, something I'm usually very capable of doing!!!!