There's a good set of pics around showing where the secondary marking is on the 6X head. I don't have the link, but I believe Bill Creech does. Maybe he'll come along and see this.
Removing 0.020" will reduce the chamber volume by about 4cc or so. But not knowing how far down the piston is at TDC or the head gasket thickness, it's hard to say exactly.where do you think im at compression ratio wise?
Could be timing, f/a ratio, or even a hot spot in the chamber(s). Again- be sure there's no vacuum leaks.in the 9:1 +. a ball park number is good for me thank you
so im guessing pining is not a detonating issue, 91 octane should be just fine right? its a timing or air to fuel mixture problem?
The power valve being old or rated too high could lean it out under load. I recommend getting the timing sorted out, install a power valve in the 55 to 65 range and then see what you have. There's no way to say if the cam is what you want or not at this point.I just pulled the tranny out today being rebuilt tomorrow it should be back in, i am going to pull all of the plugs, order the kit and diaphragm for the carb/secondaries, also a power valve a higher rating i suppose like someone said on here. then in about a week when i get paid im going to get a new distributor so theres not advancing problems. see how that works out hopefully it fixes the issue.. when i drove it today i payed close attention to when it started to ping, if im rolling or at cruising speed and floor it it will ping in the mid range and stop pining at higher range.. so maybe it is the power valve? because its not giving it the fuel when it needs it
The above should read "If the PV rating is too LOW, the PV will open at idle, causing idle quality issues."If the PV rating is too high, the PV will open at idle, causing idle quality issues.
Holley video explaining it: Holley Carburetor Power Valve | Holley TVQUESTION: How do I tell what size power valve I need?
ANSWER: To properly size a power valve, take a vacuum reading at idle and if it is above 12" for a standard transmission a 6.5" will be safe to use. For automatic transmissions take a vacuum reading in gear at idle (w/engine FULLY warmed up) and if the vacuum is below 12" divide that in half for proper size. Example 9" of vacuum in gear at idle will require a 4.5" power valve.There is a video on this procedure on Holley TV.