Interested to learn what brand/type spark plugs you are using in your Mopar - specifically 340 owners / engine builders?

Bosch Platinum in my 340/6 T/A Challenger (actually 410 cid stroker), running a Mallory Marine YL dual point, mech advance

autolite 64

cheep and efective !

i still run a set of splitfires ..since I dont run a choke, my other plugs used to foul out all the time when trying to start it..these fire right up.

I was a Champion user but switched to NGK's about 4 or 5 years ago and am very happy with them, one is 340 w/ironheads and the other is 416 w/eddy heads

Gary

Autolite's are the only ones that seem to last in my 340.

Autolite 65

Autolite. 64 or 65 - cant remember.

What compression ratio, C.I. and which type heads, stock or aluminum?

Autolite 64s in an AAR.

it has been a while since i had a small block.
if i remember correctly i used to run NGK GR4 V power plugs with a MSD 6al ignition system with a blaster coil..

Thank you for the feedback!

Compression ratio around 10:1, Stock X-Heads

When I type in 1970 340 Duster into the search criteria for Auto Zone, they recommend Autolite 65s. Is it just a different temp between the 64 vs 65?

53 Autolite. Non-Resistor plug that is no longer available. I bought boxes on them @ Carlisle years ago for a buck a piece. I've used them in bracket engines and street use for decades. 43XLS is the AC equivalent,also a non-resistor,also long out of production.

yes 64 for long drives warm weather running higher rpm

65 for short trips cold weather lower rpm use

I tried both when I first put it together and settled on the 64s, I liked the way they burned better. I'm in Florida and have been known to hammer it.

Anyone ever try E3 plugs, curious if there’s any benefit or just another gimmick.

I would run either Champion RN9YC or Autolite # 64 or if you want to run the smaller 5/8 diameter body try their # 3924

What number NGK's do you run and is it up or down from the normal heat range.