GM 350 Timing marks unreadable.a pic

[Scaaty]

OK, new complete Electronic spark system in (Prestolite in, Mallory tossed). Am I correct in the pic on timing degrees?. Also the book (from 30 years ago..VP AQ255a, new block 96, all bolt on's new last few years) calls for 8 degrees at 650 RPM. But that was the days when it called for premium fuel. Well, I run 87 octane of todays junk gas, and I was wondering if I should set it about 6 degrees. Pushing a 5000 lb 25 footer. Mostly putt around 2000R's, but smooth at 3300-3500 if I want to plane out and burn gas. Thoughts? Thanks

 

[Reel Poor]

Re: GM 350 Timing marks unreadable.a pic

If the engine was still built at 9.5:1 compressin I would say you should run at least the 89 octane fuel. Setting the base timming at 6 degrees my help eliminate spark knock but sometime it's inaudiable so you can never be sure. What is actually more important than base timming is the total advance capability of the distributer. You will need a timming light with a degree wheel built in to check total advance. Bring engine up to about 3000 rpms and check the timming. Total advance shopuld be no more than 30 to 32 degrees, this may be addressed in your manual. If it's higher than 32 degrees the distributer has to much centrifical advance and you will need to replace the advance weights to dial it in. NOTE; Check total advance after setting the base timmimg at 6/8 degrees as specified.

Also your pic is correct.

 

[Scaaty]

Re: GM 350 Timing marks unreadable.a pic

Cool...thanks!