Bear with me here i just barley learned about timing and how to do it. I'm trying to time my engine and its a 360 magnum in a 1991 dodge truck 4x4 its been dynoed before and its putting out 319 hp and 424 ft lbs of torque, as of right now i set my initial timning at 10 degrees then i reved up to 3000 rpm and set mechanical timing at 35 degrees then i backed off and checked my initial again and it dropped to 8 degrees. This is a long curve correct? and is this too much timing? 8 degreres initial plus 35 at 3000 rpm is 42 or 43 degrees total timing, strange thing is i do not hear any pinging at all while accelerating under load but that may be because i am running 91 octane fuel the compression ratio is 9 to 5 to 1. I have read that magnum engines run best with a total timing of 32 to 36 degrees of total timing, so if i wanted to get a total of say 36 degrees of total timing i would have to leave my initial where it is at 8 degrees and rev up to 3000 rpm and pull it back untill it read 30 degrees on my dial back light and then i'd have to back off on the gas and check my initial timing again and if i pull it back to 30 degrees at 3000 rpm that should dropm my initial 2 degrees so that would drop it from 8 degrees to 6 degrees and adding 6 degrees initial to 30 degrees mechanical that would be a total of 36 degrees total timing.
Should i set my total timing at 36 degrees or is it ok for me to leave it at 42 degrees because i am running higher octane fuel? i have talked to some guys who say they advance there timing untill they hear pinging and then they back it off a couple degrees and run it that way. So since i dont hear any pinging am i safe to run it at 42 degrees total timing as long as i keep running 91 octane fuel thru it?

if you have 35 degress at 3000 rpm that is your total timing

I thought you always added your initial timing to your mechanical timing to get your total timing. My mechanical timing is set at 35 degrees at 3000 rpm but when i back off the throttle and let it go back to an idle and check my initial timing its set at 8 degrees initial. So therefore id subtract 8 from 35 wich is 27 so i have 27 degrees of centrigul advance in my distributer. And when you add 35 degrees mechanical plus 8 degrees initial that is 43 degrees total timing.

It's looking lie i might need a re-curve in the distributer but for now its set at 8 degrees initial plus 35 degrees mechanical for a total timing of 43 degrees wich sounds pretty high but running higher octane fuel should make up for some of it correct? since 91 octane burns slower then 87 i should be safe to run at 42 to 43 degrees total timing on higher octane fuel.

Total timing(with vacuum advance disconnected) = initial + mechanical advance

So in your case you have Total timing of 35 = 8 initial + 27 mechanical.

If you recurved your distributor advance, to say have 21 mechanical, you could still have a Total timing of 35 but this would bring your initial up to 14. For example Total timing 35 = 14 initial + 21 mechanical.

Yes sorry the whole while having the vaccume advance plugged off.
And yes i have been told its time for a re-curve how do i do that? and where can i buy the parts for the mopar electronic distributer with vaccume advance? And i wish somone whould answer my original question, with 8 degrees initial timing and 35 degrees mechanical that is a total of 43 degrees total timing, is this too much timing while running 91 octane? i have not heard any pinging under load so i'm guessing i am not hurting anything running the toal timing that high because i am running 91 octane fuel.

43 is on the high side with todays gas even if you dont hear it ping. but 35 at 3000 is your TOTAL timing

OHHHH i get it, so i was adding it up wrong the entire time, i was adding the initial timing plus the mechanical timing, but all i have to do is add initial to the mechanical advance toi get the total timing, so yes i am running at 35 degrees. And keep in mind this is in a 4x4 truck wich i have been told its better to have a long curve in a heavy truck, correct?

So to correctly time my 360 magnum i will need to leave the initial timing at 8 degrees then slowly rev up while shining the light on the balancer and keep reving up untill the distributer stops advancing and set it to 35 degrees at the rpm where it stops advancing correct? then i add the initial timing timing to the mechanical advance to get my totoal timing and if i want to change the mechanical advance i will need to get a spring kit for my distributer correct?

you subtract initial (8) from the total (35) to get the mechanical amt (vac adv capped as you said). I'd want more than 8 initial which means the slots will need to be shortened to maintain the correct total which MAY be 31 instead of 35 on a magnum. With that finalized then lighter springs staying just under the pinging point at WOT then plug in your vac adv & staying just under the pinging point at minimum part throttle (high vacuum) at an RPM where the slots are maxed out as in out on the highway at a light throttle cruise. EDIT the light spring kit will change how fast the mechanical adv comes in & shortening the slots will reduce the amount of mechanical adv

So how do i shorten the slots in the distributer to change the amount of mechanical advance? right now its at 27 i have been told it would be best drop it down to aroun 21 to 24 that way i can bump the initial up to around 12 or 14 or even 16 and maintain 35 degrees total timing. If i dropped my total timing down to 31 or 32 that would drop my initial timing down to around 5 degrees. I will drop it to 32 degrees total timing and drive around when i change the timing i just time my 0 to 60 and see what timing total gets me there the fastest and 35 degrees total seems to be its best. Is 8 degrees initial and total timing being 35 degrees with 27 degrees mechanical advance not a good timing set up on a 360 magnum thats in a four wheel drive truck? remember this engine is not in a hot rod car but in a torquey four wheel drive truck, i am after torque more then horse power.

The truck used to belong to my father but he passed away a year and a half ago he had this same 360 magnum same ignition and distributer in an older 75 dodge truck but he took it out and had it bolted into a 91 but didnt have all the wiring finished, i finished the wiring and got it running and now i am just trying to figure out where to set the timing, i'm thinking running it at 8 degrees initial and 35 total has to be close to where he always ran it because if i could get a higher initial that would mean he had already shortend the distributer slots correct? he had this engine dynoed a few years ago and its putting out 319 horse power and 424 ft lbs of torque, found the dyno sheet in his paperwork in the garage. I'm thinking he had to of had the timing set in the same ball park that i have it at now becaused if i could turn up the initial without affecting the total timing that would have to mean that he had shortend the distributer slots already to get a higher initial. right? and he knew alot more about mopar's and this engine in particular then i do and i think if he thought he'd get more power by shortening the distributer slots then he would have done it.

To shorten the slots, it depends on the distributor. A stock distributor you typically have to weld the slots partially closed and slowly open them up with a die grinder or file. Aftermarket distributors usually use bushings to limit travel or have an adjustable tab.

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i think if he thought he'd get more power by shortening the distributer slots then he would have done it.

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Don't bet on it. Ignition timing curve seems to be black magic to most of the guys that come on here. So many guys come on here complaining about carb problems and spend hours fiddling with it even after being told on here they need to sort out their ignition timing FIRST.

trust me he's know about getting performance by shortening the slots, many guys will tell you he was the smartes mopar guy they have ever met, ether he didnt think the performance gain was worth shortening the slots or he was just being lazy and didnt cause that man knew so much about mopar, he had a 70 plymouth cuda 440-6 pack car a 71 cuda 340 car and a 70 roadrunner 440 4 barrell car and a 70 super beed with a 440 he had been around some many mopars for so many years raced them worked on them you name it.

LAZY, end of story!

If someone told me a car that wants 14-16* initial will run as good with 6* initial, I'll show you someone too lazy to sort out a distributor or ignition curve.

See for yourself how much snappier the engine will be with 14* when cracking the throttle versus the 6*. Idle quality will be a million times better. Each of those two settings require vastly different carb settings. Daytona summation that plenty of carb problems are really based in the ignition system is 100% correct!

I know PLENTY of people that will swear you should time a car based on the 1970 specs. Go ahead and do that, when another of the same car runs circles around it because the tune up is right, you'll know why.

Lazy or uneducated. There have been a TON of guys come on here who've built solid 350-500hp engines. And so many of them have that deer in the headlights response when you ask them what they've done to the ignition curve. Seems nobody wants to touch the distributor but will gladly chase the problem around by playing with jets and squirters. Stock distributors had lousy curves for stock engines, never mind modded ones.

If that was my engine, I would do the following:

Warm the engine up good and hot to normal operating temp.

Pull out the timing gun and set the timing at 10*.

Shut off and see how it restarts.

Repeat this procedure while bumping the timing up by 2* at a time until the engine starts fighting against the starter. You will know by sound/feel. Then back the timing off 2 degrees and see how it restarts hot. When you get it to start fine again with as much initial timing as possible, THIS is your initial timing.

Then shorten the advance slots to get 34-36* or so total timing. I think that's what magnums like. Too much timing can actually make less power, even though you don't hear it pinging. Typical small blocks with open chambered heads will take more timing, like 36-38.

Different springs will adjust the rate at which the advance comes in and the rpm total advance is all in at. You can have total all in at 3000rpm or at 2000rpm depending on how you set it up. In a 4x4, you probably don't need all the timing in overly early if you're going to be putting a load on it while 4x4ing.

But get your initial set to where it should be, probably in the 12-15 range and enjoy increased throttle response, cleaner burn and better low rpm power.

Ok, so i advanced the distributer to 12 degrees and it still started so i went to advance it a little more and the distributer would not advance any further then 12 degrees, whats going on here? the distributer is not hitting anything ether? i dont get it? is it possible my old man put it in there to where it could not be advanced any further then 12 degrees? do i need to pull it out and put it back in at a different position?

Are you saying the distributor physically won't turn any further? Are the plug wires binding or being pulled tight? If they are you can move each plug wire over by one pole. This will throw your timing off so you will need to rotate the distributor back a bit to make up for this.