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Si Valves

Nighthwk12

Nighthwk12

New member
I'm building up some ported heads. I Am looking to run SI valves. I have a N/A set up. Running LS6 springs. I'm just worried about the valves failing because they are under cut. What is everyones experience with them?

Thanks
 


That's my point, is there any reason why you need a larger valve? I don't think it'll hurt by any means, but I don't think they'll be beneficial persay.

If anything, manley or LS1 blanks cut to fit?
 
The intakes are already over sized from the previous owner. I was probably going with ZZP's for intake just seeing if I could get away with not changing push rods by sticking with the SI's.

Where could I pickup stock L32 valves?
 


Nighthwk12 said:
The intakes are already over sized from the previous owner. I was probably going with ZZP's for intake just seeing if I could get away with not changing push rods by sticking with the SI's.

Where could I pickup stock L32 valves?
Click to expand...

Why are you thinking that you need to change pushrods?
 


How could I possibly know if it's misinformation??? The OP is the only one registered to this forum that knows.

That is why I asked. Calm down.
 


Nighthwk12 said:
ZZP site states the valves keeper groves are at the LS1 position and states there will need to be shims or shorter push rods.
Click to expand...

That is correct. If you go with Manley, they are the same size as stock though, so your pushrods will be fine stock.
 
Oversized valves on a N/A build.

Sounds like a waste of money.

If the intake valve seat has been modified to accommodate a larger valve, you can no longer run stock valves. So that ideas out.

Whats next?

OP: To make power with NA, you're going to need an aggressive cam, and spin well past 6000 rpm. Wes Blair style. (that other company did similar numbers with no serp belt during dyno)

What intake valves are currently in the heads?
 
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I have a GT2 cam in the car now and a high stall convertor waiting for the spring. The heads were free, ported and over-sized intakes already, so no waste of money there. I do plan on using this set up as a turbo build down the road so ZZP valves or manleys are probably the way to go.
 
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