MACDAD260

Is it OK to run the stock valve springs with a new cam as long as I stay under .550 lift?

mcollinstn

It's okay to run the new style HP springs.

I wouldn't run stock 502 springs, no.

Comp 929 are good.

Ric232

Theoretically, you're okay if you stay below .544" (I think that's the number). But I'm not sure I'd be comfortable with that.

Crazyhorse

Macdad, I've got my year-old Isky 8005-A springs if you'd like a set. They all check at [email protected]. Call if you'd like a set.

Dave F

There's more to which valve springs to run than just lift. Lift is a concern for coil bind
Things like ramp speed and duration is a concern for open/closed pressures.

So, the complete answer to your question, check the cam card of the new cam. If the new cam is a GM replacement from GM, or an aftermarket very close to the original specs, it may be very possible to use stock GM springs. However, if the cam is an aftermarket cam, like Crane, or Comp with a longer duration/faster ramp speed then I suggest against it. You should also check the used springs for pressure at the height the cam card calls for.
As far as the .550 lift goes, yes, that is the "magical" lift number for hi performance GM springs. At least that's what I've always read.

DAVE

MACDAD260

Thanks for the replys, everyone.

I started out by thinking of changing the cam while I have the engine out to upgrade the oil cooler. I have a Comp cam that has similiar lift but better lobe shape than the stock 502 Mag cam. It would be a simple and cheap swap. I would just have to buy some new lifters and gaskets. I was then informed by Crazyhorse that according to Desktop Dyno the cam I have would probably not make a significant improvement. Now, if I go with a different cam it sounds like I will also have to change the springs. Well, you can't just change the springs, you have to change the retainers also. So, by the time I buy a new cam, lifters, springs, retainers and gaskets I will have about $400 dollars involved just to gain maybe 1 to 2 mph. What do you guys think? Is it worth it or should I just forget the cam and buy some new fancy wheels for my truck?

convincor

I'd buy the wheels.

I was thinking of doing a cam swap this winter also, but it's opening a can of worms.
Gen VI .. cam,lifters, springs, retainers, keepers, rockers, studs, mite as well pull the heads and clean up the valve pockets. and while there out should replace them with Manley's, and gaskets. A simple cam swap just turned into $2000+ .......

Crazyhorse

Doug, my cams are .598 hydraulic flat-tappet, so these springs would be an easy deal for you as long as your retainers will fit them.
The springs we run on Dyno's and SuperV's engines are Federal Mogul springs, VS1581 I think, and are rated at [email protected], and their cams are .556/.587.

MACDAD260

Thanks Dave,

I think I have convinced myself to buy the wheels instead. At least I can look at look at them when I'm not boating. Reliability is my main concern anyway. I don't want to have to spend all spring working on the boat this year. I just want to be ready to go when it warms up.

See ya, Doug

Crazyhorse

I know that feeling. I'd like to have everything right when the boat gets bolted together this spring.