Best Plugs for a 21 stud Flathead ??

Rustyspokes

Rustyspokes

Senior Member
What is the consensus on Spark plugs for the 21 stud Flathead motor , what are the best to use, thanks Barners ...
 
What yr there are 2 diff threads. 18 mm and 14 mm. 18 mm ive been using champ D-21's for 20 yrs never any problems.OMO ken ct.
 
Sorry Ken, All 21 studders [except 32's] have 18 mm plugs only. The 14 mm plugs are for 24 studders.
D [Al] to answer your question, I use Champion D16 or NGK A-6 , can't notice any difference between the two brands. Brian
 
Hi Ken, You are correct in as much as Ford went to 14 mm plugs in 38, this coincides with the introduction of the 24 stud motor. All 21 stud motors [with the exception of 32] had the 18 mm plugs. Brian
 
Brian said:
Hi Ken, You are correct in as much as Ford went to 14 mm plugs in 38, this coincides with the introduction of the 24 stud motor. All 21 stud motors [with the exception of 32] had the 18 mm plugs. Brian
Click to expand...
Oh ok Brian didn't realize that thanks for the info. ken ct usa
 
Re: Best Plugs for a 21 stud Flathead ?? Thanks Brian & Ken .

Thanks for the input Brian & Ken , this is the info I was looking for... D(AL)..
 
Ford dealers can supply you with Motorcraft SP 484 similar heat range as D-16 Champion. I can`t see myself using japan plugs. The Motocraft plug is also parkerised black on the hex part and looks better than the shinny D-16s. My Ford dealer had eight in stock last week. Check it out Barners.
 
You must log in or register to reply here.
Back
Top