600 eddy would be good for a stockish 318
I also like a early to mid 70s chivy q-jet with the mopar throttle lever tac welded on to the throttle shaft for stock mopar 4-v linkage
that works great on a 318 also,IMO
any smaller holley would do..
remember 318 are easy to "over cam" which means they are easy to "over carb" also
I have ran a 750cfm on a stock teen..had good top end..but the idle was pig rich and slow speed drivabilty was sluggish till 3000 rpms or so
600 eddy out the box was almost right on the jetting but still a tad rich,IMO
good luck and dont over carb it with a stock cam
dont forget to get the throttle presssure rod adjusted correctly or you will be posting about new trannys for it