... ya, I get it. One search and I read that like 20 times. Before I was thinking I would need less compression to run a large shot, but now I understand... But if you have a higher DCR then you will have more cylinder pressure, right? How much can be too much with nitrous?

What causes catastrophic failure with larger shots, like 300-500? Is it just bad tuning? To much cylinder pressure? Too high RPMs? Or just weak parts?

I have a Gen I SBC, Scat 9000 series 3.75" crank, Scat forged I-beam 6" rods, and Probe SRS forged flattop 4cc 4.04" pistons. The downer is that its 2-bolt main, but it is studded. I bought it all assembled used, but I plan to pull it apart, and use new bearings and rings. I haven't bought the heads yet, I still need to decide on C/R and quench.

With 11:1 and .040 quench I could run 93 octane on the motor but a good amount of spray would defiantly need race gas.

 

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Most failures caused by tune up is usually too much timing for the fuel used or not enough fuel for the N2O used. Pre-ignition or too lean cause issues.

Most failures caused by equipment, is weak parts. Sounds like you already know what you're in for. I myself will never spray a big hit on pistons with stock ring location, everytime we try, it fails.

My 2 cents, if you have to spray 300-500, think about new pistons & splayed billet mains.
Good luck.
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Instead of steeling the thread I could start a new one. But this may help both of us.

I just sent a shop a check to start my build and it will have 12 to1 comp callies crank, rods , splayed caps and custom nitrous pistons at what point will I have problems with head gaskets and the heads lifting. I plan on spraying 250 on the direct port and a hundred on the second stage?

This is a SBC or actually a LT1