347 spark plugs

[graysonracin]

Whats a good plug to use in a n/a 347? Colder or hotter heat range, any suggestions, or let me know what some of you are running with good results. Thanks for the help.:)

[kennebellcobra]

What heads and compression?

[graysonracin]

heads are similar to victor jrs, basically all the same specs and compression is around 10:1 i think.

[kennebellcobra]

Autolite 3924 or I perfer ngk FR5 stock # 7373

[Jeff88coupe]

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

[kennebellcobra]

I think ngk changed their stock #'s...some good info here.
http://www.dragstuff.com/techarticles/spark-plug-cross-reference.html

[graysonracin]

I read somewhere the more compression you have you should run a colder plug? Mine should be 10:1, so the 1 or 2 steps colder is the best place to start if im not going to run any power adder and pump gas, if so i think ill try the ngks or motorcraft and see how it runs.

[NXcoupe]

One step colder would be enough unless you are running spray or a blower.

[RIXXX93GT]

I have always used autolite 3924's on mine.

[graysonracin]

Thanks again everyone for the info.:bigthumb