I have changed the advance curve and max timing on my MSD dist. I wound up at 20 deg of initial timing and a max of 36.
What is your initial timing?
Compression?
Octane rating you are using..
Cam specs?

I am trying to get a picture on which way I should go with this.

Dave

11-11.5:1
278ADV cam
91 octane

i was running 16initial, but i dropped it to 14 initial after it dieseled on shut off twice...

I run an MSD distributor (PN# 85551)
22 deg initial, 38 deg total
10.0:1 SCR
94 octane Sunoco
Isky mechanical street roller
290/290 advertised
248/252 @ .050"
.602"/.646" lift
110 lobe sep (4 deg advanced)

Cranking pressure is 190psi.

I believe most stock HEIs have 12-14deg of mechanical. Mine is set at 22deg initial and I get 36 total.

Steve

Originally posted by slpin:
11-11.5:1
278ADV cam
91 octane

i was running 16initial, but i dropped it to 14 initial after it dieseled on shut off twice... No pinging on the 91 octane w/11.5:1 ?

Originally posted by SS_Dave:
</font><blockquote>quote:</font><hr />Originally posted by slpin:
11-11.5:1
278ADV cam
91 octane

i was running 16initial, but i dropped it to 14 initial after it dieseled on shut off twice... No pinging on the 91 octane w/11.5:1 ? </font>[/QUOTE]nope, no pinging, but if i put it up 2 degrees on initial, it would diesel at shutoff, and 2 degrees up that would give me pinging :/

according to steve, if i get 12-14 degrees of mechanical, i am only getting around 26-28 degrees total - which is way too little for my cam... 240@050 duration..

I run anywhere from 16-20* base 36-40* total with no pinging,92 or 93 octane
10.59 to 1 compression,210 lbs. of cranking compression
I have the UD 280/288 112 LSA

Timing is locked out at 38'
13.8-1 C/R
110 Oct.
.659in .679ex
272in 278ex @ .050

Running a UD spec 502A4LUN roller, 287/295; 256/264 @ .050, 110 lsa installed @ 105, 10.5 CR, 8.25 DCR.
MSD locked @ 37* initial.
Runs fine on LOTS of 93 pump gas.
Aluminum headed motor NEVER gets above 180* water temp.

11:1,
225 psi cranking compression,
closed chamber heads,
288/296 hydraulic cam,
16 initial 40 total, all in my 2800 RPM,
Sunoco 94 or Mobil 93
stick shift and 4.10's help for no pinging also.

** hey, looking at your sig, you and me would have one helluva dragrace!!

http://www.chevelles.com/showroom/Epistuff/No_Automatics.jpg

Originally posted by Epistuff:

** hey, looking at your sig, you and me would have one helluva dragrace!!

http://www.chevelles.com/showroom/Epistuff/No_Automatics.jpg Would be a close race, huh?
I secretly would like to snag 11's without stripping the car to do it. That's what this post is really about. Trying to wring the last couple of ponies out of it.
That last 1/4 of a second just won't seem to go away though.

Forgot to add, my static compression is 184 cold.

From the looks of all the posts, I'm on the right track. I think I am going to compile the data from here and study it for a while.

Thanks for the info!
graemlins/beers.gif 2 ya.

12 initial, 34 total
12.2:1
114 octane
Original GM 143 cam (http://dab7.cranecams.com/SpecCard/DisplayCatalogCard.asp?PN=969961&B1=Display+Card) used in L78/L72/LS6

Interestingly, this engine runs best with 32-34 degrees. Any more and the thing becomes a slug...

Okay Jim...whats with the trans pic??? :D I broke mine last weekend,,,run a th350 for 4.5 years and it lasts,go to a th400 and break it...whats up with that graemlins/clonk.gif

20 initial, 18 mechanical. MSD Pro Billet with black bushing, 2 light silver springs, all in by ~2,500. 460, 10.37:1 compression, 93 pump gas and occassionally 50/50 mix with 110 if I run 40 or more degrees timing, although I don't think it's even needed then. Better safe than sorry smile.gif

as of today, 18 initial. i unlocked the timing until i can get a real starter in the car.

Bob, stick with stuff you know works. You and Tom now. That sucks. If you knew how much stupid abuse I threw at a T350 in my old 75 358 Nova, ya would have never swtiched. No real power mind you, but STUPID 17 yr old abuse. I tried to blow it up. Couldnt. I like Jim's FLAG!

17+ 4 vac 21 idle, likes 24 better for idle quality. 18 mechanical in at 3200. 35-36 total and will test 34 at track next time. Seems to pull better there by my azzdyno. Something I can check back-to-back. Hope it does, it;s on the edge of not liking 93 octane at times it seems.

In my 468 I run approx 24 initial to get 43 total. However, 43 total was too much for the drags, so backed it down. The car actually picked up a bit of mph. I have a stock distributor with the Mallory unilite conversion firing MSD6AL.
With my converter, which is about 4000, I get the curve in by about 3500.
As far as pinging, the car has always been too loud inside to ever hear it. CR was 9:1. A lllse converter helps in that area a lot.
I have seen the black specks on the plugs though, so watch out for that. Easy to see when running pump gas because the plugs run so clean.
I also had the vac adv connected, but had to remove it when I put the 950 Holley on. No provision for ported adv on those carbs.
I think we tend to get crap gas here in Oregon. Nothing better than 92. And you never really know if it's oxygenated or not.
Ron

Originally posted by Rapid Robert:
Okay Jim...whats with the trans pic??? :D I broke mine last weekend,,,run a th350 for 4.5 years and it lasts,go to a th400 and break it...whats up with that graemlins/clonk.gif :D :D I figured that would raise a few eyebrows. Just stirring the pot. Sorry to hear about your trans breaking though. :(

468 bbc 13 to 1 compression roller cam 256/268 @ .050 cranking compression 275 psi.......timming locked at 36 degrees........91 octane in the tank .....lol but i just start it on it and drive it around NO racing .......at the track 114 purple at 4.50 a gallon uhggg.....

396 10.5 to 1 233/239 @ .050 timming now at 18 initial and 36 total........87 octane all day every day..........

woah! how did you get it to work! im running 91 octane and 11.5:1 and im having such a FUN time getting timing over 26total

15 initial, 35 total, all in by 3000. 454 +.030, 10.3:1, h/r cam 234/242 @.050, .610/.632 lift,112lsa on a 108 icl. Runs fine on 93 octane.

Update: finally got rid of the VERY NON-VOLATILE 100LL in the tank and put fresh Mobil 93 in. Still heard faint ping on part throttle ( its lean there before the power valve opens), but not neary as bad as the Sunoco fuel did ( I think that station was screwing with his fuel).

Dialed it back to 14 inital ( ex vac adv ) and 32-33 total. Feels fine, but a timeslip would show me if the motor still makes power there. Idle is a bit rattier as you would imagine.

Dialed it back to 14 inital ( ex vac adv ) and 32-33 total. Feels fine, but a timeslip would show me if the motor still makes power there.Gene: that's where our L72 loves to run. You've got a tad more initial, but we are do battle on 6" Polyglass tires, so we gotta knock the bottom end in the head as best as we can. I've played with our timing on a handful of occasions, and 32-34 is where it HAS to be. Give me the low down on your engine again...I have a theory as to why I need less timing...