I thought it sounded too good to be true but I just curious if it could be done. Around 2010 I bought a 505 kit and non-cnc ported heads from 440 Source for my 65 coronet. The kit i got is a 4.250 stoke 4.35 bore -27CC piston I figured my compression would be around 9.7 if I mill the heads down to 80CC. Back then I was saving money to get the heads cnc'd and for the rest of the components for the build then I bought a house,then got married, then had a son, and am about to have my second son so so all my car money went to better causes. I am finally in a spot where i can work on obtaining parts for my car again. This started my journey into octane requirements and if I could tweak the rest of an engine to run on 87 swill and still make good power. I haven't been able to find much about any engines running on low octane and saw this guys build and figured I'd see if it was doable. I appreciate everyone's input!
A 9.7 engine with 440 Source heads (good quench pad) should run on 87 octane IF the pistons are correct. You need to be close to zero deck (0.005 down or so) and 0.036 or 0.041 head gasket. If you do that it will work. Then you can play with cam timing and ignition curves and stuff like that but it should work.
