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LS6 springs, cam and heads

baxsom

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I have a 00 LS1, so far it only has bolt on modifications (LS6 intake, headers etc) I picked up from a local shop a perfect condition 02 LS6 cam and a set of 01 LS6 heads. I know that the 01 LS6 heads dont have the lighter valves but are they the same length as the 02+ LS6 valves. Also, the heads have a brand new set of LS6 yellow springs. Should I go ahead and switch them out for a set of pac 1218s. I was told that the yellow springs will not work with the higher lift 02 cam and the solid 01 valves. I know I could have went with a bigger cam but so far between cam, and heads i have 150 bucks total invested. Im not looking to break the dyno record when I get it tuned, I am more interested in the swap itself, not the end results. Thanks,
 

Hib Halverson

Technical Writer for Internet & Print Media
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71 04 12 19
The 02-04 valve stem length is different.

To use the 02-04 LS6 camshaft in an LS1, you need the cam, the valves and the springs from the 02-04 LS6.

If you're going to use the heads with the 01 valves and springs, you must use the 01 LS6 camshaft.
 

baxsom

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Joined
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Messages
388
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Cocoa Beach FL
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72 454 convertible, 2000 C5 Z51
Thanks for the insight. For springs I was going to go with the PAC 1218s just because of all of the broken LS6 spring threads I have ever read. It is very hard to find the 02+ hollow and sodium filled valves so what I was told I could do is use a different length pushrod to take up the difference. Texas Speed told me to use their pushrod checker gauge.
 

baxsom

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Joined
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Messages
388
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Cocoa Beach FL
Corvette
72 454 convertible, 2000 C5 Z51
I have read that article a few times. It reads that they increased the length of the valves to accommodate the smaller base circle. So if you use shorter valves like the ones in the 01 and older heads you need longer pushrods to accommodate. It then goes on to read that without the lighter valves you get issues in the higher rpms. That is why the internet is full of people saying to toss the GM springs and put in a better brand like the new comp 918s or the PAC 1218s. So back to my original question. If I use 01 valvetrain, will longer pushrods make up the difference in valve geometry without having to do anything else to the rockers like shimming?
 
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You just need to check the pushrod length. The PAC 1218s are for a maximum lift of .600, if you are using a stock LS6 cam from any year LS6 you dont need the after market springs, the stock springs will be fine. The 1218s or 918s wont hurt, but the specs of the stock cam dont require it.

Just check the pushrod length and make sure the existing springs are not binding.
 

Hib Halverson

Technical Writer for Internet & Print Media
Joined
Jan 10, 2001
Messages
13,457
Location
CenCoast CA
Corvette
71 04 12 19
In theory, would could bastardize your valvetrain with longer pushrods and a significant increase in valve spring pressure, but know that the 02-04 valve mass is significantly less due to the hollow stems.

You'll need a lot of valve spring to both overcome the increased mass of the LS1 valves and keep the valvetrain stable to 6600 rpm with the more aggressive 02-04 cam.
 

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