So I have a 10 to 1 forged internal 355 with vortec heads eddy rpm intake eddy 600 care 1.6 rr and a cc503 (pn 08-503-8) my question what should my initial or base timing be set. Also running 3.42 t56 thanks to all that can help.

 

computer controlled? as high as you can get it without pinging or detonation

non-computer controlled? http://outintheshop.com/faq/hei.htm

 

OK let me go about this a bit differently. I have a street fire hei. Stock has a 21ish degree advance with vortex heads I can only run a 13 degree initial.... well I'm having a loss in power under load free revs nice idles OK . If I bump it up to about 16ish it starts better. But I'm afraid to run it with to much mechanical being as I would need a stop of somekind but I need to figure out where the cam I have should be for performance/daily base timing so I can then try to rig a stop of some kind or order a new distributor that will be drop in ready from say dui. So i hope that clears up where I'm at. Cause if I can figure out where I should be base timing wise the rest will fall in to place for me thanks.

 

It might not be timing it might also be fuel. Get a wideband in there or check plugs but hard to use plugs to find dead spots

Typically i would try something like 20-25 at idle and 30-32 wot if an efi controlled car. I dont play with mechanical or vacuum advance distributor types but i would venture to suggest 16 initial at idle and max advance of 30-32 for starters at 3500+ rpm and see how it runs. Good comp with iron heads that have good chambers it likely wont want alot of timing. 34 on a stock iron L98 head seemed to work well for a 350 L98 car i just tuned with a cam 1 step smaller than that

 

if your mechanical advance is bringing it to around 34 degrees advanced while revving it in the garage, it will be doing the same under load.

did you read the link? everything is pretty much explained within.

 

Yes I did thanks for that info. Might have a fuel issues than as stated above. I have a aem wide band on car just not hooked up yet I guess I'll go from there after I finish installing. One last question before I finish this where should afr be right around 12-13 correct?

 

proper AFR will depend on load. In most cases, 12 will be too low. look for 13-13.5 under load as a ball park.

 

and if you don't have timing tape, 34 degrees is damned close to 2.4 inches from the zero mark on an 8" balancer.

 

Thanks alot for the help guys . I'll report back after wide band is operable.

 

I have a tdc mark so I bought a digital dial back timing light

 

Initial (base, static) timing is likely to want to be about 18°, and total about 33°, with about 12 - 15° of vac adv on top of that.

If you have 21° of mech adv, that's too much. You're going to have to limit WOT adv to 33°ish, otherwise it'll ping and detonate; then the "centrifugal retard" will take it down to 12° or so static. Not enough.

Don't waste your time with a "dial back" light. They're HORRIBLY inaccurate. Garbage.

It's pretty easy to mark a crank damper... use a compass and bisect the angle like you learned in HS geometry... half a rev is 180°, half of that is 90°, half of that is 45°, half of that is 22.5°, half of that is 11.25°... when you get to 45° just keep dividing the range you actually care about, which is from 0 to 45° BTDC, in half, until the increments you have marked out are small enough. IMO once you get to the 11.25° point you can pretty much eyeball it to within a ° or 2 which is PLENTY close enough given the tolerance and slop in everything else.

 

I was reading about using the pre drilled hole in the advance and putting a roll pin there. That may limit me just enough to do as u disribed. Got my a/f gauge hooked up waiting for a warm day to tinker. How about timing tape would that be worth it.

 

Timing tape is good... no matter what method you use though, be sure you ACCURATELY locate TDC, NOT just "assume" that the existing mark is correct.