[n20ta2]

Im looking for a little advice timing my highport 461.
What have you found is a good starting point before tuning? Im running a msd pro billet distributer with advance weights operational at this point. Looking for a good initial setting. Thanks!

[mysticmissle]

Something in the low 30s depending on compression

[JLMounce]

Start around 28 degrees and work up from there. My understanding is that the chamber in the high ports is very similar, if not identical to the KRE D-ports. It's a cold, efficient chamber that doesn't need a lot of spark advance. Cam timing events, piston to deck clearance and chamber size will play a role in what the engine wants.

If your block is zero decked, you're probably going to wind up pretty close to 30 degrees total. If your piston is in the hole, you'll likely end up with another couple degrees.

On my KRE D 462, my pistons are .005 to .007 in the hole and it likes right at 32 degrees of total advance. I've played with bringing it in around 2800 to as late as 3200 and the but dyno doesn't register a difference and the engine doesn't seem to care either. So it's somewhat trial and error. I'd start at 26 to 28 degrees total, in by 3000 rpm and increase in 2 degree increments until the car slows down or doesn't get faster, then back off 2 degrees.

[n20ta2]

Great thanks guys, I'm 0 decked and compression is a tick under 11.01

[25stevem]

Every engine run at the drag strip will have too different best timing settings.

One that produces the best and most consistent 60 ft times, and one that makes for the highest mph.

These two settings may only be 2 degrees apart if the head in question has a good chamber in terms of pressure recovery and more importantly fuel management.

Also with Aluminum heads until you get deep into eleminations the chamber does not get up to max temp until near the end of the run in terms of making maximum power.

In other words once your making passes every 30 minutes you might find that the timing setting that made the for the best times now needs to be 2 degrees less.

And yes this detail hinges on the weather factors during the course of the day or evening as the case may be.

Along these same lines, even running fuel with a higher octane then what the motor needs can call for 2 degrees more timing being needed.

[n20ta2]

Originally Posted by 25stevem

Every engine run at the drag strip will have too different best timing settings.

One that produces the best and most consistent 60 ft times, and one that makes for the highest mph.

These two settings may only be 2 degrees apart if the head in question has a good chamber in terms of pressure recovery and more importantly fuel management.

Also with Aluminum heads until you get deep into eleminations the chamber does not get up to max temp until near the end of the run in terms of making maximum power.

In other words once your making passes every 30 minutes you might find that the timing setting that made the for the best times now needs to be 2 degrees less.

And yes this detail hinges on the weather factors during the course of the day or evening as the case may be.

Along these same lines, even running fuel with a higher octane then what the motor needs can call for 2 degrees more timing being needed.

Right, thanks! Just looking for a good initial setting for now until it goes to the track next summer, just got it running so needed a decent starting point.

[slowbird]

Originally Posted by n20ta2

Right, thanks! Just looking for a good initial setting for now until it goes to the track next summer, just got it running so needed a decent starting point.

29-30° is a good starting point