Which spark plug and what gap?
Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
the 350 Vortec heads typically call for Autolite 605`s, gapped at .060"
that plug gap is excessive, IMO.
try Autolite 103`s, gapped at .030-.035" thats the gap the 86 vette used. (.035")
the smaller the gap, the better, for eliminating "flashover"...
that plug gap is excessive, IMO.
try Autolite 103`s, gapped at .030-.035" thats the gap the 86 vette used. (.035")
the smaller the gap, the better, for eliminating "flashover"...
Drifting
Joined: Jan 2005
Posts: 1,348
Likes: 322
From: San Antonio Tx
This is from the GM parts direct website for a crate motor with vortec heads.
R44TS Gap @ .045 (300 HP 350)
41-932 Gap @ .060 (330 Hp 350)
R44LTS Gap @ .045 (330 Hp 350)
Rapid Fire #8 @ .035
R44TS Gap @ .045 (300 HP 350)
41-932 Gap @ .060 (330 Hp 350)
R44LTS Gap @ .045 (330 Hp 350)
Rapid Fire #8 @ .035
Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
the 103`s are a little colder, so if your engine is runing too rich, you might have issues with fouling.
but they are listed as replacements on some GM`s from the 80`s-90`s, and lots of Ford models since the 70`s, all the way up to today..
104`s will fit too, but they are typially designed to gap at about .045"...
but they are listed as replacements on some GM`s from the 80`s-90`s, and lots of Ford models since the 70`s, all the way up to today..
104`s will fit too, but they are typially designed to gap at about .045"...
Drifting
Joined: Jan 2005
Posts: 1,348
Likes: 322
From: San Antonio Tx
BigLee, you are correct. The R44TS is what the parts store gave me and I had to take them back. I believe the R44LTS is the long reach? Popular hot rodding used the Autolite 103's in their vortec buildup. Mine are gapped at .035 (using small cap dist. with external coil)
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Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
i`m not certain, but the R44LTS may not work either...
IIRC, that plug is for L98/LT1 aluminum head engines.
they had the long threads, but use a flat gasket seat, instead of
the tapered seat, like Vortec, and newer engines.
IIRC, that plug is for L98/LT1 aluminum head engines.
they had the long threads, but use a flat gasket seat, instead of
the tapered seat, like Vortec, and newer engines.
