[JLMounce]

One thing to keep in mind is that as the cylinder bore increases, the flame propagation slows down, which requires a bit more timing lead to reach maximum power.

I've been doing a good bit of tuning on my engine this summer and most of what is working well for power and heat management has been almost exactly the reverse of what many people believe is what needs to be done with these cars. Including myself.

My combination is a +0.040 455 with the factory 4.21" stroke. It uses KRE D-ports with a 2.11/1.66 valve arrangement with Jeff's 310 cfm port. Port matched Torker II, a moderate 240/248 on 112 hydraulic roller and a FiTech system fuels and provides spark.

What I've found is that having more timing in the curve, while simultaneously slowing that curve down has resulted in the best power and street manners. I've also fattened it up more than I did in the past. I'm not saying that works for every engine, but it's working well for mine.

I idle the car around 13.5:1 afr with 22 degrees of timing in it. at 1100 rpm and increasing MAP, I don't drop the timing down further. I command 25 degrees at 1100 rpm and 95kPa MAP readings. At 3000 rpm the spark curve is around 34 degrees and between 3000 and 6000 rpm another 3 degrees is added. This puts my 36 degree total timing figure right at around peak torque that occurs at 4600 rpm.

My engine is very knock tolerant and it will handle a lot of timing, which is one of the reason I'm able to have a bit more in it everywhere. But in my case a slower curve is working a bit better. At cruise, I'm only adding around 5 degrees of additional advance and I'm targeting between 13.7-14:1 AFR. Fuel mileage has actually picked up a bit even though I'm running the engine a little richer.

For WOT AFR I command 12.5:1 that tappers richer to around 12.3:1 by 6000 rpm.