Alloy heads do not need big timing on the street.
I too have a 360 with alloy heads, with 3.55s, but with a 4-speed.
If your heads are closed chambers, and your pistons are at or near zero-deck, then you are pushing a chitload of cylinder pressure with that tiny cam. In which case, mine didn't seem to care about the Power-timing from 32 to 36 so most of the time she is at 34 degrees.
But if your pistons are still stock 8/1's;
well yur on your own lol. In this case, the alloy heads are sucking up an easy one point of compression, until you put some heat into the chambers, at which time, they are still sucking an easy half a point.
So, as far as the engine thinks, if it could think, most of the time, an 8/1 engine it behaving like a 7/1 engine. Therefore, it's gonna want extra advance all the time, in the "cold Chambers."
Now, when I'm talking cold or hot here, this has nothing to do with the coolant temperature. This has everything to do with the chamber temperature.
Loafing along, the chamber temperature is cool, while the coolant temp is at or near the minimum coolant temp set by the thermostat. when you hit the gas, the chamber temp scoots up in a heartbeat. Normally, cast-iron heads are not gonna change their temp much in the 3 to 5 seconds that you are gonna be at WOT, so the chamber temp is gonna rise quickly.
But alloy heads will suck that heat out, and put it into the air all around them , and into the cooling system. This reduces your chamber temperature. Heat is power so, to compensate for this, it has for years been said, that you need an extra half a point of compression.
Well, I'm pretty sure, that's not enough, cuz my engine likes up to 11.3, the highest I have tried, and have run it up to 195 psi cranking cylinder pressure, still on 87E10; and With NO DETONATION, at up to 36* advance at WOT.
So like I said, if your pistons are down in the hole, you're on yur own..
But I can tell you that, about 1 degree per 100 rpm, starting from 20* at 2000 rpm, is gonna be close. So then
25* at 2500 will be fine going to 34* at 3400 is pretty much guaranteed to be close. If you get detonation under power somewhere, between stall and "all-in", just slow the rate of advance down to say 8/10th degree per 100, and delay the all in for a couple of hundred rpm.
If this makes her sluggish with the 3.55s, I'm not surprised, just get a higher-stall convertor, like say a 2800/ problem solved.
What the timing is at idle, the engine doesn't much give a fiddlefart about, so long as;
the engine doesn't stall when you put it into gear, and
doesn't clang/bang the trans when you put it into gear, and
she drives away smoothly when you granny take-off.
If you can get your Transfer slots properly set, it will do this with any timing from 5 to 15, and I never even take the vacuum gauge out of the toolbox. That gauge is for diagnostics, and, as regards a performance street engine like yours, is not much good for anything else.
Best of luck to you.
