Flat-Tappet
Member
I drove my newly acquired '72 'Cuda today, and am getting the feel of it bit by bit. As I was getting more aggressive with the throttle openings, I believe I heard some light knock "pinking" at around 3500+ RPM.
The motor is a 440>496 stroker with CR listed at 10.4:1 with Diamond pistons, iron heads and timing supposedly at 34 all in (will confirm once I get my timing light back in my hands).
Dyno sheets show conflicting fuel information, with both BP 93 and 100 listed on the sheet. Its possible they could have been using a blend. I thought all along I might be on the ragged edge of knock, and i believe my ears just may have confirmed that. I did not hear it when the PO took me for a WOT rip, but there were many other sensory inputs going on, so I could have easily missed it.
I have access to Sunoco 110 leaded gas which I run in two other cars exclusively, so its availability is part of the answer for me. But I'd prefer not to run the 'Cuda exclusively on 110 leaded gas.
Instead, I intend to put, say, 2-3 gallons of 110 Sunoco into a tank with 8 gallons of 93 as a mix, to bump up the octane to 96-97 and see if that pinking goes away. i think its going to be a bit of trial and error at first. Then perhaps a session with a sharp chassis dyno guy may help me get a grip on all this.
Any suggestions or input on blending leaded fuel with unleaded pump gas? is it stable?
Does the lead in the 110 add some added "juice" to the unleaded pump gas beyond the pure ratio that the blended numbers alone create? In short do you get a bit of "serendipity" with the addition of lead?
The motor is a 440>496 stroker with CR listed at 10.4:1 with Diamond pistons, iron heads and timing supposedly at 34 all in (will confirm once I get my timing light back in my hands).
Dyno sheets show conflicting fuel information, with both BP 93 and 100 listed on the sheet. Its possible they could have been using a blend. I thought all along I might be on the ragged edge of knock, and i believe my ears just may have confirmed that. I did not hear it when the PO took me for a WOT rip, but there were many other sensory inputs going on, so I could have easily missed it.
I have access to Sunoco 110 leaded gas which I run in two other cars exclusively, so its availability is part of the answer for me. But I'd prefer not to run the 'Cuda exclusively on 110 leaded gas.
Instead, I intend to put, say, 2-3 gallons of 110 Sunoco into a tank with 8 gallons of 93 as a mix, to bump up the octane to 96-97 and see if that pinking goes away. i think its going to be a bit of trial and error at first. Then perhaps a session with a sharp chassis dyno guy may help me get a grip on all this.
Any suggestions or input on blending leaded fuel with unleaded pump gas? is it stable?
Does the lead in the 110 add some added "juice" to the unleaded pump gas beyond the pure ratio that the blended numbers alone create? In short do you get a bit of "serendipity" with the addition of lead?
