I've heard stories that go both ways. The original V8 in the 55-59 cab used a very small-diameter distributor, and even the 1960's-70's style medium-sized "window" distributor with the Allen wrench adjustable points was a tight fit. My main concern with the big HEI unit would be contact between the cab and the cap on a hard pull due to engine torque.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!