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Old 09-02-2012, 11:32 AM
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Advance travel stop

F-BIRD'88, I have confirmed out total timing is 36 BTDC on the timing tape and idle timing is at 18.

On your sentence
If you want more initial (24ish) for a more snappy throttle response then limit the advance travel stop so mech advance is limited to 10-12deg travel. (the stock adv travel limit is 18 to 22deg typical)
Do you mean to set the initial timing higher and then install a mech advance travel stop to not exceed the 36 degrees total ? (i.e. if I set it at 24 then I would put in 12)? Just making sure I read that right.

Also, F-BIRD'88 and COBALT327, on the vacuum advance, I read the part in the article below but have not yet tackled that. Adding what you said makes total sense; I just now need to figure out how to read what my vacuum is before I install the vacuum advance stop plate (if needed) and setting the appropriate curve.
I am thinking of attaching a vacuum gauge to the port and then going through some driving scenarios and recording the numbers to see where I'm at - does that sound reasonable or is there a way to do it in the driveway (i.e. does the engine need to be under load?).
btw, I am using the ported vacuum port on the holley.
I have included a copy/picture of the vacuum advance settings for my HEI distributor; does the degree column correspond to initial timing? (in which case my row would be the 18 degree row). It doesn't say how many turns the canister has when you buy it though but it looks like the max is 15 degrees so at least I won't be over the max.

Hmm, sparkplugs is another whole research I'm working on. I currently run AC Delco R45TS's gapped at 0.45 because, well, I had to start somewhere and that seemed to be the consensus out there for non-boosted chevy's but I now need to understand why. Why such a cold plug F-BIRD'88? every article I have read says at most a R43 for a chevy and down from that only if you have boosting.
I did read that you can check your plug to see if it is fouling (too cold) or melting (too hot) and the old ones I pulled out were perfect so I stuck with the same one. Once I have the engine timing perfected (which is looking really soon!!) then I plan on playing with that.
I found the following method to determine gap:
Have someone crank the engine, while you hold the end of the coil wire close to a grounded spot. Using a wooden ruler, (and wearing gloves), measure exactly how far you can draw a visible spark. Then divide that number by the first figure in the engines' compression ratio. For example, if you can get a visible spark .600" long, and the compression ratio is 9:1, then .600 / 9 = .064
For that I need to figure out my compression and I have thread # 1587377 on the go for that. Somewhat of a challenge that is

A 750 holley is in the works as budget permits

As always, thanks for the help! it is much appreciated.
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