Octane requirements for nitrous and high SCR?
 

New build is a 434 with ported 670 iron heads at 9.8:1 compression. Lunati 231/239/110 on 104.5 ICL. With an intake valve closing of 65.5* ABDC, the DCR should be about 7.8:1.

What octane fuel should be used with a 150 shot of nitrous? Single stage plate under a Q-jet on RPM intake.

Hmm, I sense some hesitation to answer this one. So let me ask another way: Can I run a 150 shot on 93 octane pump gas, or do I need straight VP110 LL?
OR, am I limited to a 100 HP shot on pump gas?

Assume engine is sealed up well and tuned properly.

If it may help,
I ran a 9.5:1 412 250cfm 6X head with 230/236 110 ls installed at 106 hf cam on 92 octane. 150 shot and pulled 4 deg. Of timing without issue.

I have a 461ci 11.3 to 1 pump gas (93 octane) motor with a 150 shot . But i have a separate fuel pump and cell with 108 that mixes with the 93 for the NOS. Works great.. Never tried it with straight 93. Id be skeptical just like you.

I ran a 462 with 9.5 comp. and a 275 shot on 92 octane with 8* out and
no problems, I was using a separate pump just for the nitras.
I've always run two pumps on my car for nitras. and always pulled 8*
and haven't had a problem yet. Hope this helps.

GT.

I've run more comp. with this combo too.

GT.

Blueghost, How big a cam were you running? Do you know the adv duration and LSA? Trying to compare intake closing event to what I have.

There were deferent ones. I'll get the cam cards out tomorrow and let ya know.

GT.

Man I had forgot all about this.
I'll be in my garage tomorrow and get some of this info for ya, Sorry bout dat.

GT.

Sorry I will get it eventually for you.

GT.

FWIW, my old Discomobile was pushing 11.5:1 CR with iron heads and I ran VP C-16 racing gas in it, spraying up to a 250-HP shot. No issues

Good info guys, keep it coming.