Headers off -- changing Spark Plugs -- what type are best?

[94GTLaserRC]

General rule for plugs, Stock range is for iron heads and no power adder - Autolite 3925, One range colder would be for either aluminum heads or a power adder, not both - Autolite 3924, and Two ranges colder for both aluminum heads and a power adder - Autolite 3923. Gapping for power adders is as said smaller than stock to help prevent spark blow out.

Thanks..
That explaination is fairly straight forward and Crystal Clear!
RC

 

[FastmanGT]

Thanks..
That explaination is fairly straight forward and Crystal Clear!
RC

Anytime man...

 

[94GTLaserRC]

Vib told me today, the 39xx are for ALum heads, and for my Stock heads, I need the REGULAR 24's by Autolite.

The Mnf chart says 25's, and one step colder would be 24's.

RC

 

[FastmanGT]

I think Vib is right on this, I had a brain fart I guess , the iron head plugs are the 25 - stock, 24 - iron plus power adder, gapping according to the power adder. Sorry about that...

 

[94GTLaserRC]

I think Vib is right on this, I had a brain fart I guess , the iron head plugs are the 25 - stock, 24 - iron plus power adder, gapping according to the power adder..... :

Which is 0.032 as above, Correct?
RC

 

[94GTLaserRC]

Spark Plug Brands- Conversion Question

I pulled off the spark plugs today, and they were NGK brand. The type was NGK R UR5

Does anyone know what the AUTOLITE equivalent is?
Im guessing it is the Autolite 25, since that is the MNF recommended one for my car.

RC

 

[94GTLaserRC]

Running good so far, and it seems strange, but it actually looks like the ECT may be running a little lower.
RC

 

[Slow5.0]

Sorry guys for bringing this post alive but I need help
I just installed TW heads and I put 3923 plugs
What is difference between 3923 and 3924
And what gap is supposed to be on my TW heads N/A