INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

Valvetrain questions.

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Old Oct 31, 2013 | 01:31 AM
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Okay, so my build will have a Lunati cam in a LQ9:

Advertised Duration (Int/Exh): 272/278
Duration @ .050 (Int/Exh): 222/228
Gross Valve Lift (Int/Exh): .567"/.567"
LSA/ICL: 113/109
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 2000-6600


Going to be runing my 317s with .040 gaskets. Couple questions I have as its my daily drive not a strip, track vehicle. What springs will have longevity>? I rather go a stock route if I get the mileage out of them. Just not wanting to change springs every 3 oil changes. Can I run a stock spring with this cam or NO. And what are the best springs for what Im looking for?

Im also doing the lifters... Im going with the new updated design supposed better than the ls7 lifters. Same dimensions as the ls7 lifters. That being said.

What length pushrods do I need to order to put this combo back together?

So Im searching for what type of springs are best for this cam, and what length pushrods I need to purchase.
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Old Oct 31, 2013 | 01:38 AM
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You will need at least a PAC 1218 or 1518 spring. I would just run the PAC 1518's, a little overkill never hurt anyone.

Now since your going to be running the LS7 lifters you will get many different answers on the length pushrods you need. The best answer will be, you need to measure.

Now with that said I run 7.425 pushrods in my LQ9 with stock heads/gaskets and I am running LS7 lifters. They maintain the right amount of preload for me.

Odds are you would end up needing 7.400 pushrods, but regardless you really should measure.
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Old Oct 31, 2013 | 01:44 AM
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I always like to get a good dual spring for longevity. Gold or platinum springs are best for the long haul. Push rods should be measured even if 7.4 is mostly standard.
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Old Oct 31, 2013 | 01:45 AM
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ok so PAC 1518's.... with new design ls7 lifters. So the pushrods will be the last thing ordered. After I get them measured. Thanks for the info bud. Still open for any ideas or comments, I will be ordering parts next week, so just gathering all the info I can.
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Old Oct 31, 2013 | 01:47 AM
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Originally Posted by gamble686
I always like to get a good dual spring for longevity. Gold or platinum springs are best for the long haul. Push rods should be measured even if 7.4 is mostly standard.
can you elaborate? I thought duals were harsher on the valve-train and not what you would want for longevity?
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Old Oct 31, 2013 | 03:27 AM
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Originally Posted by sleeperlqx
can you elaborate? I thought duals were harsher on the valve-train and not what you would want for longevity?
Standard beehives are expected to last around 15,000 miles. Dual springs are more reliable and the newest ones are expected to last around 40,000 miles.
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Old Oct 31, 2013 | 04:25 AM
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what is the process like for measuring pushrod length correctly?
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Old Oct 31, 2013 | 05:39 AM
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Originally Posted by sleeperlqx
can you elaborate? I thought duals were harsher on the valve-train and not what you would want for longevity?
Your lift isn't that aggressive so duals would be a overkill and a lot harder on the valve train with that little lift.
PAC 1218's would be fine, they're good to 600 lift I believe so you have plenty without getting close to coil bind... FWIW, I had singles with a Comp 220dur and 581 lift and I ran it for 50K no problems.
Originally Posted by Noah Burns
what is the process like for measuring pushrod length correctly?
How do you check pushrod length - Corvette Forum
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Old Nov 10, 2013 | 10:47 AM
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Will the pac 1518 springs work with a Comp cam speced:

227/235 .614/.621 113lsa 109c

54-458-11 - LSR

Need all the info I can get. The lift is pretty decent and I dont want to worry about PTV issues.
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Old Nov 10, 2013 | 04:21 PM
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Get brian tooley racing dual springs. They will work great and only cost $130
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