ACCEL 276S or equivalent (are Autolite 24s equivalent? are they 5/8 reach?)

[91LX_5L]

I just came across the manual on my heads and noticed that they call for "Cast iron heads use a 5/8 reach plug such as an Accel 276 or equivalent" are the autolite 24s equivalent to these? Are they 5/8 reach?
http://www.worldcastings.com/tech/w...linderheads.doc

thanks

 

[91LX_5L]

ttt