good deal vs heap

good deal and heap both are nouns.

Word	Noun	Adjective	Verb	Adverb
good deal	Yes	No	No	No
heap	Yes	No	Yes	No

As nouns, good deal and heap are synonyms defined as:

good deal and heap: (often followed by `of') a large number or amount or extent

good deal (noun)	heap (noun)
(often followed by `of') a large number or amount or extent	a car that is old and unreliable
	a collection of objects laid on top of each other
	(often followed by `of') a large number or amount or extent