Plugs: -1 or -2 colder ?

MartianBob

Registered User
I'm about to replace a set of stock motocraft 34 pp's and put on some magnacores too. I have read many spark plug threads already.

I'm trying to determine If I should go 1 or 2 steps colder. What happens if you go too cold on plugs?

After installing my 5% pully I'm experiencing some detonation at WOT above 3,000 rpm (generating almost 15 psi). It gets worse when going up hill. I have have a hi-flow exhaust from the manifolds to the muffs., and just put in a new fuel filter.

I was going to by a set of autolite APP764. These have the shorter tip. After reading some posts, I was considering the APP103 plug (shorter tip and colder). I live in central Cali. and it never really gets below freezing here.

I just don't want to replace the plugs any more than neccessary.

thanks for any advice.

Bob

94 5 spd, hi-flow exhaust, IC fan, - air box, 5% pulley.
 
I went with Denso irridium plugs with my setup..Go rid of my high end bucking/detonation problems...If you do go colder go two steps as one really isnt considered much of a change in heat range..ALthough Im sure there are opinions on that
 
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