what other sorts of paper developers do you have on hand ?
what format film?

dektol might give you lots of chunky big grain ... but other PAPER developers might too ..

you might try over exposing and over developing your film
in whatever developer you use, and process it a bit warmer than 68 ...
i hate to advertise coffee, but you might also give caffenol c a whirl
it gives nice grain .. not sure how chunky but nice ...
and it sometimes looks weird, thin, foggy, but enlarges like a dream

bill is on the money, wide angle and enlarger too

have fun !