Hey guys so I dropped my 250 back into my truck yesterday, it is my first rebuild so I am pretty excited. However I went to thread the spark plugs in and they were too big. I switched from the integral head to a non integral one casting number 3895054. I cant find any info on that number anywhere and I was just curious as to why my old spark plugs wouldn't thread into the new head.

Thanks,
Dustin

some plugs are a long reach and some are a short reach. Or other wise known as a peanut plug. But anyway one is a 5/8 plug and the other is 13/16 which is the longer reach plug.

Yep that was it twisted.....I feel dumb now. Thanks though, I was trying to use spark plugs from old integral head and they were different threads