Total Timing- Big Block

Would like to get several opinions on how much total timing is used on your Big Blocks, and how much is too much.

I would definitely start with the tried & tru 36-38 for a sensible start. I would (1) set the initial with the "vacuum gauge method" then with that figure in hand (2) shorten the slots to get 36-38 (3) then springs (4) then hookup/adj vac adv (2 adjustments on it)

I'm at 34-35, 20 initial (lumpy cam). I haven't tinkered with total advance, just set it there and it runs well.

Does the engine have quench? Without Quench 36 is typical, with it 30-32 commonly works better because of the faster burn...

You should try a few different settings and see what it likes. I found 36-38 made the engine run choppy, even though I couldn't hear any detonation. 34 was a smooth running setting. Hard to say what CA gas will do for your's. Combustion chambers can make a difference.

My 440 runs like a bear at 38 with a 528 mech cam.

Very little ( ok NONE ) info given on the engine and setup.

That said my 69 383HP with 56k miles and factory 9.3 compression picked up when I bumped the timing from 36 to 39 , It was recommended that I could got as high as 42 , but I was too to try that.

I've et'ed best with my no-quench, iron head 440 with 42°.

It depends on many things what each motor wants, compression, combustion chamber design, fuel quality and octane, spark plug heat range, elevation the car is driven in and how much your butt dyno can detect on tuning changes I have built,dyno tested and tuned, driven and raced a bunch of different BB motors, mild to wild, 325 HP to 845 HP I would start at 34 total and go drive it, retard to 32 and drive it, then 36, maybe 38 and see what you and the car like Higher elevations (less thick air and B.P.) usually will tolerate a little more total timing than the same motor at or near sea level BTW, I like a lean mixture and a cold spark plug with the total timing that gives the best results

Your mileage may vary, and CB is right, it needs to be determined experimentally.

From reading countless dyno test results published in all kinds of car mags over the years, the generally accepted total ignition lead required by an open chamber big block Mopar is 38 degrees. That big open chamber has little swirl or other mixture motion and needs a relatively long time to get everything lit off.

R.

I run 34 (10.2, pump gas with quench).

Wherever you start, suggest you verify TDC with the positive stop method. On my stuff, the timing marks were off nearly 10 degrees.