i went to replace my plugs today, read on here that the ac delco cr44ts's are good for 10:1 compression motors. so i went to autozone, and what they gave me was the r44ts's which i thought were the same. i pulled out my old plugs, which were autolite 3924's and went to replace them when i noticed the autolites have about twice the thread, going in twice as far. im guessing the r44's wont work, is that the difference between the r44's and the cr44's?

im using trick flow 23 degree aluminum heads btw

 

I wouldnt try it, if it were me i'd just go back and get the right ones.

 

i just ended up getting the autolites again, guy at autozone was a total dick about it.

 

Most aftermarket aluminum heads used the "long reach" thread plugs these days. For example, I use those same 3924s in my AFR 190 heads.

Don't sweat it- I use cheap-o Autolites in my motors all the time. I've never had a problem with them. I can not say the same for high buck "specialty" and "platimum" plugs. The 3924s like to gap around .040 or thereabouts, which is fine for a N/A engine dired by an HEI distributor.

If you want a slightly colder plug remember that the last 2 digits of an Autolite part number are the heat range. Next step down would be 3922s, for example. 3924s are already about 1-2 steps colder than most "stock" heat range plugs. An Autolite with a '26' on the end would be a typical stock replacement heat range.

 

im not entirely sure about whether i need a hot or cold plug, i have most of my mods in my sig. im running a 10:1 compression ratio. ill tell you one thing though, im not replacing those things again until i absolutely have to, what a PITA