Heavy or lightweight flywheel?
I'm staying with my 30 lb steel one for now... 2.66 1st, 3.91 gears.
My 316 advertised/107 cam (
[email protected], .652 lift) needs all the off-idle help it can get, even in a 451. Best stable idle is at 1200 but I can get away with 1100. Retard the timing and it just noses over and dies. So no parades for me ;)
I haven't tuned anything that Big; not in cam size nor cubes nor power, so anything I mighta said in the past, generally, you can ignore,; unless I said it to you specifically,lol..
When I had the 292/292/108 installed, that 367 of mine had a bit of an idle-lope.
But with the current 276/286/110, I can't hear it, nor feel it, until the rpm is way down; Ima thinking the factory FW is smoothing it right out.
What I find is that (not yours) that if the Transfers to mixtures is off, that yes there is a sharp drop off related to retarding the timing. But the closer the sync is, the slower it will run by retarding the timing.
The only reason I don't retard mine to less than 5*BTDC, is that's all I got left in my electronic dial back,which is normally set to 14*. The box has a range of 15*. I allocated 9 to retard and 6 to advance. I use the 6 advance during the warm-up period, so it idles on 20*. And I use up to 9* retard for parading, which is then still 5* advanced.
But I know that my 367 will idle on less than 5* if I wanted it too, because at 5* it still has enough power to pull itself, on a flat, level, hard surface. BTW; Your starter-gear with 2.66 x3.91=10.40 is about the same as mine (10.97). That is a sweet street starter-gear.
IDK anything about to how to tune your combo, but if I was allowed just one guess, I'd guess she might have a low-speed fueling issue, directly related to ......... to your piston being about half way up the cylinder on the intake stroke, before the valve finally closes, lol.