4.2L and 4.0L spark plugs?

[Sandboxcowboy]

Wondering (without goin to CT just to find answer) if the spark plugs from 4.2 are same thread size and electrode length as the early 4.0L's? (Pre H.O.)
IE- Will they screw in and not be too long and smash off inside?

Wierd question but its a Heep and im experimenting here..... Until i can get donor XJ

J.

[havnfun]

I checked two mfgs and they list the same plug 4 the 87 4.2 and the 91 4.0l wranglers