Spark plug gap with vortec heads/carb
 

What should my gap be. I'm running Autolite 605's.

Also what about timing. I'm at 8* initial right now. Seems as when I advance the timing the truck doesn't want to start.. My mechanic thinks I need a higher cranking power battery. The battery I have is a $30 refurbished one.

Timing initial and total
spark plug gap. The reason I ask about the gap is because they were set at .060 out of the box.

Re: Spark plug gap with vortec heads/carb
 

Well It depend on your Ignition Hei, spark box, points? If you have points I'd open them up to aounrd .035 with hei .045 and experiment from there. there are other factors like compression ratio and stuff when choosing plug gap size. As for cranking power your battery might be a little under powered, If you can try a buddies battery try that and see if it solves your problem. As for timing set it to where it idles good but its not so far advanced that your starter lugs real bad when your firing it up again when the engine is hot.

Re: Spark plug gap with vortec heads/carb
 

This is exactly what happened when I fired it, set it where it should have been , it ran fine, but starter lugged when I shut it off and tried restartin it.

Tuning wise, I really did not want to run headers, but just curious what I would gain. I'm runnin the plugs at .40 thou. Maybe I should go .45.

Thanks for the information. Compression wise, I'm about 10.1.

Re: Spark plug gap with vortec heads/carb
 

Hmm well you could try retarding the timing a bit just to keep it from lugging, and headers won't really do much unless you have aftermarket heads,cam, high perf intake, and a peformance carb. If its just stock with 10:1 CP than headers wont gain you much.