Experts and Know-it-alls welcome..

Greenhorn here..wet behind the ears...etc...but trying to learn as much as possible..
So, based on posts and opinions on this site, I have purchased an Edelbrock LD4B intake for my 73 318 block. Also, topping it with an Edelbrock 1406 carb..fresh and ready. The 73 engine that's sitting in my 72 Demon has mismatched heads.. One 675 cast 318 head and a 1967 273 head..maybe it works, maybe not...have not tried firing it up since purchased in January. ( does turn over by hand ..fingers crossed ). So again, based on some suggestions I just bought a set of 302 casting heads... These heads were gone though and seals, seats replaced...valve job etc.. though it was done 10 plus years ago and they've been sitting ever since.. Sprayed?? ( whatever that means ) and wrapped in plastic.. They look extremely clean and fresh to me.. Paid $500 for them...and he threw in a Mopar brand engine gasket kit..lol
Anyway, these don't have rocker assemblies.. Can I just use the ones off my 318 and 273 heads that came on my engine..? Should I buy new..find a set on here that someone may have..? And, this guy mentioned something about maybe needing different length pushrods..
I'd like to put in a MILD cam.. To be honest, I'm not really going for hp, just want something a little lumpy..love the sound..! Recommendations on cam that I wouldn't have to change anything else to get the lumpyness... 318, 3spd manual w/ 3.23
A lot written here, I apologize..but just wanting some help. Thanks..!!