Injector Limit for Cast Oval Bowl Pistons???

Grimes_County LBZ

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Also posted this in the LBZ forum, but figured I throw it in here too since this is a build forum.

Picked up a stock LB7 short block recently for my LBZ project truck. Intend to build this utilizing a forged SOCAL crank and forged carillo rods, but want to use cast piston to get some more longevity out of the engine. Curious to see if anyone knows how much injector the Finger's Oval Bowls will take? Could I get away with 60% over's, 100% overs? Bigger? Just looking for some guidance.

To provide a little more info, because I know this question is dependent on a lot of variables... intend to top it off with a set of PPE cast iron heads, and likely a Ryan's 64mm 9 blade. May consider a compound setup in the future, but we'll cross that bridge when we get there. Already have a built trans.

I look forward to the replies. Thanks in advance for the support.

-Shane
 

TheBac

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Sorry, that duplicate thread is gone. No need for multiple threads in different sections for the same topic.

From what I understand, Jon's ovals can handle just about anything injector-wise you can throw at them. Im sure Brad or someone else who's been north of 1000hp will stop and back that.
 
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Grimes_County LBZ

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Sorry, that duplicate thread is gone. No need for multiple threads in different sections for the same topic.

From what I understand, Jon's ovals can handle just about anything injector-wise you can throw at them. Im sure Brad or someone else who's been north of 1000hp will stop and back that.
@TheBac thanks for the reply! That seems like way more than what I'm looking to make, but at that power level, I would assume 150% over injectors at a minimum. Should be plenty strong enough to do what I need. Thanks again.
 

Chevy1925

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Fingers pistons have gone into the 2k range with no issue iirc.

100% overs on a single 64 is a good route. Leaves room to grow for compounds. Tbh, a 1500uS tune on a single 64 and 100% overs will be smokey. Add a compound and its going to make another 100hp on the same tune just from cleaning up the smoke
 

2004LB7

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My recollection is that John said no one has really found the upper limit of his pistons. Basically a rod, crank or something else failed before the piston when pushed. I think the only real failures where form something like a stuck injector torching the piston or other hardware failure hurting it. But none has outright failed on their own.
 
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MarkBroviak

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I’m surprised that no one has opined about the cast iron heads and 9 blade. 😝 Getting soft around here 🤣
Honestly not any real world info on the cast iron heads in a street truck that I have even seen or heard of. Everyone I know that tried to get a set of them couldn't even get them. The 9blade turbine, sound and performance is awesome but reliability is yet to be proven good yet. For the question asked about what injector size for the turbo size, 100%injectors are more than plenty for the power range of the turbo. Yes, we have made around 2khp with the oval race cast pistons.