Mac 2002 SS

iTrader: (6)

i was wondering would prc double springs rated at .650 lift, be to much pressure for a 224 cam with .566 /.566 lift on a ls6 heads ? most of sponsors offers thier own brand of .580 lift springs or cc918 springs for an option rated at .600-.625 lift with ls6 heads . i just want to make sure what ever i go with would be the right choice for me. thanks in advance .

PREDATOR-Z

No, you can use them

Old SStroker

Ask the person/company that spec'd your cam for spring advice. Over-springing may not be the best thing for power and long-term relaiability. Bigger ain't always better.

PREDATOR-Z

Yes, but the part that will pay the price are the lifters and on cam only almost no one changes them.


Anyways in this case those springs are 365lbs (open pressure) which is not extreme for a XE lobed cam (or similar). A 918 is 318lbs (open pressure).

So yeah, you can use them.

Old SStroker

You did the XE cam for Mac? What's the spring mass and the retainer mass for those springs? What's the installed spring load? I'm not familiar with what parts you used, but I am with the 918 and associated retainer. How high does Mac plan to rev it?

Mac 2002 SS

iTrader: (6)

are you talking about me or another ,Mac ? anyway my cam is an XE and hopefully once it is installed and tuned , i shouldn't have to rev it pass 6300 or 6400 rpms to make good power .

so it seems that if i were to get prc's ls6 heads with the prc's double springs or the cc918's or if i went with Livernios LS6 stage 1 heads with .580 lift springs, i should be fine.....right ?

Mac 2002 SS

iTrader: (6)

yeah ,thats what i was thinking too. over springing can actually hurt your performance as well. as crazy as it may sound ,but i do belive it to be true. if i'm wrong ,please someone tell me otherwise cause i need to know. i'll give tsp a call monday and talk to tech person and see what they say. thanks again guys for you input.

PREDATOR-Z

No, it is obvious from the specs he gave, that cam is limited to 64>6500 max, anything more is a waste.

SS, I said I agree with your comment in general. In this application, it will do him no harm to use PRC duals if he so wishes.
Me I would use beehive, titanium retainers and hollow/sodium valves. The lighter the effective moving valvetrain mass, the better. but that is an expensive valvetrain compare to solid stainless valves (He is talking about stage 1 243 heads).

cam

iTrader: (9)

I bought stg 2 heads used assembled with 918's and stock retainers. Running a TR224 112 and when we put it on the dyno I had float so I priced out new 918's with ti retainers and spoke with numerous engine shops and found not much love for the 918 so I went for Patriot Golds and I love em! Best of all is the better price.

Its nice to know when I bounce off the limiter at 6900 now and then that I really have no worries. Overkill? Perhaps but I'd take a toasted lifter over valve to piston contact anyday

Mac 2002 SS

iTrader: (6)

i guess you have a point there ,cam. after seeing all the post on 918's ,i'm not totally convienced on 918 springs anymore. but ,there are so many you have had success with them as well. i don't know what to think.

tell me more about the beehive springs ,guys ..??

Old SStroker

Sorry, it wasn't obvious to me. I found a few lobes with those specs. I guess it also depends on what Rocker ratio was being used for that lift.

FWIW, compare the mass of a steel retainer for a 918 beehive with the mass of the Ti retainer for dual springs like the PRCs mentioned. IMO, you might not need the costly Ti for the 'hives, especially with the power peak rpm you are going to get with most 224° cams. Of course opinions are like belly butons...everyone has one. It can be to the customer's benefit if he is only sold the stuff that he needs to make the engine combination work correctly, and not "gold plate" it. Again, just my opinion.

Yeahdoug

I'd use a PAC-1518.