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Old 04-24-2014, 10:30 AM   #1
BigSix
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Join Date: Mar 2014
Location: MD/VA/PA Or Inbetween
Posts: 413
Hotter timing/plugs with my Holley 2 barrel? GMC V6

Got a good 350 Holley 2 barrel on the old 305E. Runs well but its time to check timing and make sure its on right. Just wondering if anyone has gone to a different timing setting (i have a manual trans so I believe it is 2.5B? - please correct me if wrong). Also time for new plugs so I figure why not see if you guys have found a way to make the spark and timing hotter to make even more power?
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Old 04-24-2014, 11:47 AM   #2
BigSix
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Join Date: Mar 2014
Location: MD/VA/PA Or Inbetween
Posts: 413
Re: Hotter timing/plugs with my Holley 2 barrel? GMC V6

Quote:
Originally Posted by Sharps40 View Post
Been down that road with a perfectly good Inline 6. Cracked 4 pistons at 8000 miles due to over advanced timing and over lean jetting.

If you don't have a firm grasp of Initial Timing + Mechanical Advance + Vacuum Advance and the fuel ratios at various RPMs provided by the jets in the carbs, I'd highly recommend you stick with Factory Book Initial advance setting....especially if its now running well and with no ping now.

AcampoDave, this board came to the rescue with factory timing recommendations for my new I6 and I finally settled on only 2 degrees more initial advance than the factory recommended for an I6 with electronic ignition. Motor is very happy there and I have good power and no ping.

As for plugs, I switched to the factory equivalant plug from NKG, the V-Power brand and gapped them 45 thousands for the HEI ignition I have installed. I'd probably run the narrower factory gap on an engine with points ignition.

None of the sixes will wrap yer guts around yer spine and as I found out, too much advance will lead to catastrophic engine failure.....especially if you don't consider all the other variables that work with or against initial timing.
Definitely don't want too much advance for sure. What seems interesting to me is that automatic trucks take 7.5 and manual takes 2.5...

Wondering if going somewhere in between there would give me just a little more how that I have decent fueling.
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