what spark plugs are best for a 302

[scrapper]

Its a 1975 engine with trucks heads, headers, carb, a cam and flat top pistons, hei disributor. what would be a good sparkplug?

 

[scrapper]

so far i have found autolite 24 with a 54 gap

 

[lil_Blue_Ford]

Motorcraft or Autolite is usually what’s recommended for the older Fords. Double platinum is considered the best. The Iridums aren’t worth the price. Single platinum is all the benefits of platinum with all the downside of copper (better spark, faster wear)

 

[scrapper]

Motorcraft or Autolite is usually what’s recommended for the older Fords. Double platinum is considered the best. The Iridums aren’t worth the price. Single platinum is all the benefits of platinum with all the downside of copper (better spark, faster wear)

would 24 be correct? I found autolite ar24 im guessing they should work?

 

[lil_Blue_Ford]

Standard for a stock truck back then was a 26, APP26 for Autolite double platinum. Don’t remember how the heat ranges run with the numbers though, so a 24 may be a hotter or colder plug that may work better/worse with your application. Sorry I can’t be of more help.

 

[scrapper]

oreillys says ap 25 Im just not sure because everything is different from stock. I put in 94 f150 302 engine because that is what the heads come off of.

 

[scrapper]

Standard for a stock truck back then was a 26, APP26 for Autolite double platinum. Don’t remember how the heat ranges run with the numbers though, so a 24 may be a hotter or colder plug that may work better/worse with your application. Sorry I can’t be of more help.

Thanks for the help it should work with a 26. Just thought i would ask to make sure.

 

[lil_Blue_Ford]

Thanks for the help it should work with a 26. Just thought i would ask to make sure.

I went by the older block…

 

[scrapper]

i meant ap25 is what oreillys said. its around an 8 for the heat but some were a lot hotter

 

[Uncle Gump]

With a carb and HEI i would just buy copper plugs. I'd likely start on the cooler side... then go hotter if they foul. Once you figure them out... you could run platinum if you want. But with a carb ... you'll probably have to change them more then every 100k anyway. No sense in spending the extra money when copper plugs will be just fine.

 

[19Walt93]

I agree about running copper core plugs, they'll last 30k or so. I run Motorcraft plugs with a 42 heat range in both my truck's 351 and Mustang's 302 with much higher compresssion. The truck has ASF42C's in the basically stock but carbureted 95 F150 engine and the Mustang has AWSF42C's in it's GT40 heads.The 94 heads are a huge improvement over 75's, the ports are better and they used pedestal rockers instead of the valve guide eating rail rockers from 1975. A 73-76 302 block has a .023" taller deck height which would drop compression a little unless your pistons compensate for it.

 

[85_Ranger4x4]

I went by the older block…

Gotta go by the cylinder heads, over the years they had different reach and sealing methods.

Difference in spark plugs between a '86 Mustang GT and a '87 Mustang GT... note how one seals down by the threads and one seals back by the hex. They are not even close to interchangable. The groady ones are for E7 heads which should be the same as a '94 F-150. Trucks may spec a different one so don't go by that.



Copper plugs for the '94 heads, Motorcraft if you can.

 

[lil_Blue_Ford]

Gotta go by the cylinder heads, over the years they had different reach and sealing methods.

Difference in spark plugs between a '86 Mustang GT and a '87 Mustang GT... note how one seals down by the threads and one seals back by the hex. They are not even close to interchangable. The groady ones are for E7 heads which should be the same as a '94 F-150. Trucks may spec a different one so don't go by that.



Copper plugs for the '94 heads, Motorcraft if you can.

I stand corrected…