goyamaha

Finally dropped in my rebuilt big block in my 68 Coupe and got her to fire once fuel made it to the carb. I had to retard the timing just a little from an eyeball adjustment where I had basically set the dist as close to dead on #1 as possible. I am just wondering how to adjust the timing now. Is there a typical setting that works well? I have a timing light and know how to use it but I just don't know where to set the timing.

Engine info:

1970 402 / .30 over (yes 402...it's a long story)
10.5:1
612/612 hydraulic roller cam with full roller rockers
Edelbrock Torquer II intake with a Holley 750 - Vac Secondary
Stock distributor with Accel electronic points eliminator kit (no vacuum advance)
Muncie M20
Stock timing gears

Thanks!

Les

Most big blocks like around 34 degrees total, give or take 1-2 degrees. I'm also running w/o vacuum advance because with my cam I couldn't find the sweet spot until I eliminated that. I'm running at 16 degrees initial and 34-35 total and it runs great. That should get you in the ballpark until you can find what it likes best. Good luck.

BarryK

try this:

http://forums.corvetteforum.com/c3-t...long-post.html

goyamaha

Thanks Les. And BarryK, wow...that's the motherload. Thanks!

TheSkunkWorks

Good info in that thread, but do bear in mind not all engines have the exact same ignition timing requirements, and some BB builds simply won't tolerate too quick of an advance curve (mechanical). That said, I'd agree that 16* initial with 34* total (again, mechanical) should be a very good starting point for you.

midyearvette

...thats a great starting point, don't be surprised if it really likes 38-40 total depending on which heads you have, open or closed chamber
with your compression where it is, i don't think it would like anything over 40 degrees total
try all in at 36-3800 (slow curve)
15-20 initial