I need your guys help quick.... Please!!

crunchie12268

New Member
Aug 4, 2004
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Manhattan, KS
okay guys, I have to get to the track, but I need to know if I should switch up my plugs first. See, I have GT40 Cast iron Heads, I have TF55 NGK Plugs, these are a step colder than what the NGK manual says I should be using with the GT40's, (actually I looked up what the cobra uses and it said the TF45's I think). But I was wondering if stepping up a heat range will make any difference... these are the same plugs that were in the car when I bought it and it ran good, so I don't know if I want to mess with it. Anybody? I need to know so I can get it fixed ASAP. Thanks
 
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2000xp8

SN Certified Technician
Aug 8, 2003
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NJ
My guys, would say yes to using the right plug, they also use autolites on everyones gt40 heads (p,x's,y's).

I don't know from experience, but when i had the y's i think they had me get 23's because i was NA, just never put the car together that way.
 

crunchie12268

New Member
Aug 4, 2004
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Manhattan, KS
Sorry, i got some numbers crossed..... TR55 are in it and the book says UR45, but I get them and they are about half an inch shorter from base to tip. I don't know if I should put them in.