Ford Mustang Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
319 Posts
Discussion Starter #1
I'm just curious about what spark plugs some of you guys are using. I have a 347 with Victor Jr. heads. I run high 10's going threw the traps at 7100rpm. I occasionally have the problem of burning the tip of a plug. I was told it was because they were cheap passenger car plugs that should not be in a race engine (Champions). What plugs and heat ranges are you guys racing with a 347 with Victor Jr. heads using?
 

·
Registered
Joined
·
1,666 Posts
not a 347, but I use the autolite AR3923 plugs. They are autolite "race" plugs. never had any good luck with champions in a ford.
 

·
Registered
Joined
·
1,157 Posts
I run Autolite 3924's on a set of Canfields. Go through the traps at 7700. I have to richen it up a little as my plugs were a little to white for my liking.
 

·
Registered
Joined
·
4,226 Posts
TFS, Edelbrock, and AFR Heads:
[14mm, 3/4" Reach, 5/8" Hex, gasket seat]
AUTOLITE
1 step colder--3924 (4) [*recommended starting point]
2 step colder--3923 (3)
-----AR3933 (3) [*recessed tip, racing plug]
-----AR3932 (2) [*recessed tip, racing plug]
-----AR3931 (1) [*recessed tip, racing plug]

NGK
1 step colder--(FR5) 3686 (5) [*recommended starting point]
2 step colder--(BKR6EY) 3696 (6)
-----(R5671A-8) 4554 (8) [*recessed tip, racing plug]
-----(R5671A-9) 5238 (9) [*recessed tip, racing plug]
-----(R5671A-10) 5820 (10) [*recessed tip, racing plug]

MOTORCRAFT
1 step colder--AWSF22C
2 step colder--AWSF32C



My 347 is similar to yours...only I'm FI. I run autolight 3924's n/a...3923's on the spray. They work good for me..and are cheap. Plus just about every autoparts store carries them..heck even walmart does.
 

·
Registered
Joined
·
319 Posts
Discussion Starter #6
Thanks for the feedback guys. Going to try the Autolites this weekend.
 
1 - 7 of 7 Posts
Top