So after a good amount of diagnosing the previous misfires with the freshly fired up 408 I decided to have my extra set of 823 heads rebuilt. Finished installing them early this morning and a compression test showed them all around or under 200. Right after closing the drain valve on one of the catch catch cans I could tell the idle was a lot more consistent and pretty much smooth. But I am still left wondering if it should feel like it does or do all larger v8's have a somewhat consistent kick or lope? I know it could use a ton of touchup on the timing like smoothing the transitions and figuring out which adaptives to change. I am running it on 93 available down the street thankfully.
I am very impressed by the output of this motor compared to the 6.0 it was. I have about 75 miles on it so far, did an oil change at about 50 hoping the second oil change looks like it should I will be taking an early sample in a few days just to see how it looks. Today was the first time I had it over 4k rpm actually put a little bit of foot into it. I was not aware I hit 99% TPS until after looking at the log. Do these motors usually require a bit of desensitization in the misfire tables or does this still look like a misfiring engine? Lastly I wanted to ask how accurate the part in the log may be where the engine hits 538ft lbs of torque at 4,258rpm about 3:18 into the "clip" log? Questionable idle misfires are in the "end" log.
If I had to guess an optimal idle for this size engine and near stock duration cam on 212/218 I would guess 700-750 rpm?
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