Should I start with a 89 vette spark table and go from there?? What do aluminum heads like - - is it more at cruise and less total (for some reason that sound familiar).

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355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), Mufflex 4' cat back, B&M shift Kit, 2500 converter, and 3.27s.

 

For cruise add some all the while monitoring TPS if it starts to increase you went too far. You want the least TPS / speed.
At WOT take 6d out and start tuning, with a Comp cam 270 vette heads, mine liked 28-32
and usually the 28 (weather was a factor).
HTH
Bruce

 

Grumpy when you say between 28 and 32 do you mean as it is seen on the chip, not total right? Do you have a stock vette chip in that bin collection of yours? Id like to take a look at the spark tables on one of those just as a reference.

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355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), Mufflex 4' cat back, B&M shift Kit, 2500 converter, and 3.27s.

 

I think he ment total.

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1987 IROC-Z L98,SuperRam,EB 6085's,LPE 219/219 Roller, Crane 1.6RR, EB TPI Base, 58mm TB, ADS 24#, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, MSD 6AL, MSD Blaster 3, Aluminum DS, 94 Disk Rear, Adjustable Valve, Precision 3.73 Gears, Sub-Frame Connectors, Hotchkis Lower Control Arms, KYB Shocks/Struts, Suspension Techniques Lowering Springs, Polyurethan Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm,

To see the ROC, Check out the webpage Here

 

TOTAL.
With the small chamber, and lessened surface area you don't need alot of timing, at WOT. The smaller surface area means that more heat is used to move the piston, rather then be absorbed by the cooling system. Smaller chamber means less time needed to burn what's in the chamber.

Kinda a short story but that's the high points. (Also, smoothing the chamber helps alot, since it further reduces the surface area).

Tuning for Max amount of timing is for when you know no better, or consider your engine disposable. I can run much more timing then peak power, but long term, just shortens engine life and wastes fuel.
HTH

 

The 89vette chip that I am looking at has around what your saying for WOT timing(29) on the table. So total is 35, right? Also cruise looks awfully high, in 40 to 48 area. Thats 46 - 54 when added to base timing! Am I reading this thing wrong!? Thanks for the help.
On another subject, how lean can you safetly run in highway mode? I thought I saw someone on this board running like 17:1. Im not even gonna change that stuff (highway mode) yet but I am curious

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355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), Mufflex 4' cat back, B&M shift Kit, 2500 converter, and 3.27s.

 

Grumpy is right. There is a point where advancing the spark does not increase engine output any more. In fact, most max outputs can occur over a 2-4 degree range of spark advance, so you want to/need to error on the lees advance side, which does not hurt power, anyway. I believe this theory is called Minimum Best Spark, for least advance for Best power... It has been a while. The the higher/more-advance spark advance value is called Maximim Best Spark, which correlates to Best engine output.