Quote:
|
.......recent hot rod builds of aluminum head engines, your machinist is in left field, crap gas or not. An engine built with aluminum head is significantly more tolerant of poor octane fuel than an engine with iron heads, even without regard to the dynamic compression influence via camshaft timing. .....
|
Yup, I learned that in 2001 or so. I had 87cc E-heads on a 428 with a 248/254@ .050, 114 solid roller, and that setup ran best with 87 octane fuel, and slowed down with 91. From that experience, I got a set of 72cc E-heads which brought static CR to 11.4:1 which works great with 91 octane.
Another interesting thing is, this engine now runs best with 31 deg ignition timing, where with the 87cc heads, I needed 36 deg.