Is this the right spark plug?

[justin_nelson]

I have a 250 inline 6 and went to local parts store and told them i needed plugs and this is what they gave me. They are the same overall length but the threads are longer than the ones that were in it. they thread all the way in but i just want to make sure they arent going to be hitting anything inside because the threads are longer.
thanks for all your help
justin



and heres a pic of my freshly painted motor

[Mike J]

I can't see the pics on the computer here at work- but you don't want the electrode end to be too long- it could possibly come in contact with the piston, and that won't be good. I would make sure that got the part number correct for your application.

[too much stuff]

I would get the number off the old plug and cross reference or get the same ones. Make sure of the year of the engine and if you are running HEI or not.
Eric

[Wrenchbender Ret]

They changed the length of the threads on these engines around 1970 to the shorter plug. Often the older heads were put on a later engine. Check the length in the head. Also the longer plugs had a flat seat & used a gasket.

[camrycurt]

Originally Posted by too much stuff

I would get the number off the old plug and cross reference or get the same ones.

x2 on the cross-referencing. It took me three tries to get the right plugs for my new truck because the engine is not original and is from some old car, etc., etc.

IIRC, the Autolite website had a really good cross-reference and lookup feature that helped me a lot when I was trying to find the right plugs for my engine.

Good luck! Your engine looks great by the way.