1969 396-375 AC Plug

[69z28fan]

Can someone tell me what the correct plugs are for a 1969 396-375. Will R43xls work in this motor?

[WorkinProgress]

R43 is the correct plug for iron heads. Not sure what R43XLS is, but the R43XL is used with aluminum heads. XL stands for extra long threads.

                                      - Warren

[WorkinProgress]

Made a mistake. R43 is a 302 spark plug. R43N is the correct plug for 396/375 with iron heads. R43XL is for aluminum heads.

                                              - Warren

[69z28fan]

Thank you.