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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: mikewb on August 05, 2008, 09:55:29 pm

Title: spark plug
Post by: mikewb on August 05, 2008, 09:55:29 pm

what decides the gap for the engine? if i have vortec heads on a carbureted engine. do i gap them at 60 or 45?

Title: Re: spark plug
Post by: VileZambonie on August 05, 2008, 09:59:54 pm

.060" is the gap. The plug the ignition system and the combustion chamber help determine appropriate gap.

Title: Re: spark plug
Post by: SUX2BU99 on August 06, 2008, 01:32:30 pm

.060 eh? Hmmm I'll have to check mine to see what my mechanic gapped them too. I remember my Dakota R/T was something like .035.

Title: Re: spark plug
Post by: mikewb on August 06, 2008, 06:27:18 pm

old style was .45" but the vortec motors were 60" soo which do i use with just the vortec heads on my old block with carburetor and hei.

Title: Re: spark plug
Post by: jefferias on August 06, 2008, 06:51:36 pm

dont quote me on this but my understanding is that the older ignition systems need closer gap because of power output from dizzy and coil and whatnot. so that being said it depends on the power your throwing thru your wires to the plug.  ive been doing lots of research on this and i seem to find a general consensus that .04 - .05 "works best" on sbc.  i personally have mine set at .042 and everything seems to be legit.    just my 2 cents worth man!

Title: Re: spark plug
Post by: VileZambonie on August 06, 2008, 08:38:15 pm

Set em at .060"

Title: Re: spark plug
Post by: mikewb on August 07, 2008, 03:58:34 pm

think soo vile?

Title: Re: spark plug
Post by: VileZambonie on August 07, 2008, 04:42:34 pm

I know so. I have Vortec heads. Use AC Delco 41-932 gapped at .060"

Title: Re: spark plug
Post by: mikewb on August 07, 2008, 07:09:20 pm

with hei distributor? i have ac delco r43TS

Title: Re: spark plug
Post by: VileZambonie on August 07, 2008, 10:48:11 pm

Well you are using the wrong plugs. You need to use the plugs I listed or their equivalent. Your HEI is quite capable of running these for normal driving.

Title: Re: spark plug
Post by: mikewb on August 08, 2008, 04:59:49 pm

whats the difference in the plug? and will it run different gapped further?

Title: Re: spark plug
Post by: 82Shortbed on August 08, 2008, 11:51:43 pm

R45TS Plugs are not long enough to go in the chamber properly.  You need I believe a .700 reach on the plug, the R45TS plugs only have a .460 reach.

Title: Re: spark plug
Post by: mikewb on August 09, 2008, 03:54:28 pm

sooo one with 500. will run better? because it runs fine now.

Title: Re: spark plug
Post by: VileZambonie on August 09, 2008, 04:17:27 pm

It may run fine but you are not optimizing your combustion

Title: Re: spark plug
Post by: mikewb on August 09, 2008, 04:21:34 pm

soo then it should run better with the other ones?

Title: Re: spark plug
Post by: VileZambonie on August 09, 2008, 04:23:02 pm

Not sure if you'll notice a difference but those are the correct plugs for those heads.

Title: Re: spark plug
Post by: 82Shortbed on August 09, 2008, 10:08:29 pm

Plugs I've seen other guys use other than the 41-932s are

Autolite 605s
NGK TR6, TR5, TR55GP
AC R43-R45 LTS. (Notice the L.....I just tell people it means Long Tapered Seat)