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E30M30
05-04-2006, 12:34 AM
I'm about to check my ignition advance curve, but I'd like to hear how you guys think the curve should look like.
My motor is a pontiac 455 with trw race pistons (Little uncertain about compression, but should be a little but over 10:1). Edelbrock performer RPM heads and intake, proform 4bbl carb. Hedman hussler headers and flowmaster 40's. My cam should be 280 degrees at zero lift with hydraulic lifters and roller rockers. MSD 6AL ignition. Rear end is 3.08, gearbox is a T-10
I think it's advancing to fast now. Below 3000 rpm it pings (maybe it's just the headers ??). Maybe the engine specs craves running the gears out, but I would like to enjoy the torque... This is my first US car, so I'm a bit of a beginner..
Thanks Stefan

Mike Holleman
05-04-2006, 04:20 PM
My 421 Pontiac engine is set up at 18 degrees of mech advance coming in at 2800 rpm. My total timing is 34 degrees. You most likely could go a bit higher on total timing. As much as 38 degrees works good but you will need to run 93 octane.
Mike Holleman

OldSchoolFormula
05-06-2006, 03:17 PM
www.performanceyears.com or www.classicalpontiac.com should be able to help you out immensely.

Cheatin'Chad
06-19-2006, 07:01 PM
I like what Mike is saying here.

What is your plug gap currently set at? What part# plug are you running?

68Formula
10-17-2006, 03:45 AM
Agree with Mike, since he has a great name. Start out with 16° initial with total of 36-37° by 2700-3000 rpm. I would not expect pinging at WOT unless you're running less than premium fuel.

Get an adjustable vacuum advance and adjust it for part throttle. (That is probably where it is pinging, right?) I like the Crane kit because you can adjust the rate and the total. Most others require you just control the spring preload which affects the total and the rate.

sporter
10-19-2006, 06:54 PM
Yep, 14-18 initial with 32-38 total is a typical curve for Pontiacs. On a chassis dyno my factory iron headed 455 made the most power with 16 initial and 38 at 2500 rpm (435 rwhp & 495 rwtq). The Edelbrock heads tend to want more timing than other heads, up to 40 degrees. What cc are the Edelbrock heads, 72 or 87? The 87cc chambers will give you about 10:1, which is about equal to 9:1 with iron heads, so you should be ok up to 40 degrees. The 72cc heads are over 11:1 and will most likely ping with pump gas. What jets are you running in the Proform carb? Better to be a bit too rich than too lean. What temp is your engine running? Some 455s run hot, try to keep it below 210 for best performance.

MonzaRacer
11-10-2006, 03:21 PM
Well i would start with about 12 to 18 initial (I go by if it starts after hot soak) then I usually use stock weights in gM distributors and mix and match weights inside till it suits me, for best results I like to get advance as fast as I can without spark knock. I agree with the antiknock characteristics of the Aluminum heads. If you have oe distributor you may have to open up the advance slot some.
Then after iaget all this going and get idles speed and mixture adjusted(I do it in gear, hot) then add in your vacuum advance to manifold vacuum then readjust the idle speed and mixture again. This way you can get the most benefit from the heads.Most of the pontiac heads from Edelbrock can take as much as 65 degrees total at a light cruise if cylinder preasures dont get to o high. But one ofthe adjustable vac advances helps complete the tune.
Good luck.
Lee

pitts64
12-28-2006, 04:55 PM
For those of you new to Pontiacs this is a great link.
http://home.comcast.net/%7e69bird3/jimhand.htm