100 Octane LL AV Gas

[VintageMusclecar]

I've been running 100ll in my Chevelle basically since I got the car back on the road in 2012.



I dyno'ed the 496 in the Chevelle with 100ll and it ran flawlessly.


I've ran 100ll on the dyno numerous other times on other projects, each with 0 issues.


I've A/B/A compared 100ll to 93 Sunoco premium in my Chevelle; on 100ll the car cold starts with minimal fuss and doesn't take much babying when it's cold before it builds enough heat to idle on its own. Idle characteristics are perfect. Hot re-starts are instantaneous. It is worth noting that the currently remaining 1/4 tank of 100ll in the car now is over 3 years old and it still starts and runs fine.



With 93, cold starts require quite a bit of throttle pumping and significant babysitting time when cold before it'll idle on its own. Hot re-starts require holding the throttle open +/- 1/3 and cranking until it starts, and idle quality is noticeably diminished. WOT performance seems to be fine, however.


An aside: combusted 93 octane stinks. 100ll smells fantastic.



Conversely, 93 octane feeding the 358" small block in my wagon is 100% uneventful, the car runs fine on it. Never tried 100ll in the wagon, don't see a need to at this point.


Lastly, I dyno'ed Albert Galdi's 950+ HP supercharged 540 on straight 91 octane fuel from a no-name gas station near the dyno facility. We ran it at 36° timing and +/- 160° water temp with just under 5 lbs. boost, air/fuel ratio was in the high 11's under WOT, and the engine ran perfectly with zero issues. The plugs came out looking absolutely perfect.


In a nutshell; the need for 100ll is somewhat application-specific, but in all the times I've used it in the last +/- 40 years, I've never had a problem with it.


My $.02, FWIW, YMMV.