can someone give me the run down on heads 160 vs 180's etc

Runner volume means almost nothing as far as how a head performs, but unfortunately industry standard is to differentiate cylinder heads by their runner volume. It's just one of those things that causes a lot of confusion but will never change. What makes it even worse is that often it is implied that the bigger the runner volume, the more air the head flows and at a slower velocity, but this is also a fallacy.

To understand why, you need to look at how a cylinder head is designed. Runner volume is the product of runner cross sectional area and runner length. If you try to compare an AFR 185 to a Twisted Wedge 185, it's really apples and oranges, because the TW has a shorter port with a larger cross section. Technically, the TW is a "larger" head, but from a runner volume standpoint, they appear similar.

What makes it even more confusing is that cylinder head manufacturers OFTEN round up or round down runner volume when they name their heads. An AFR 185 likely isn't exactly 185CCs.

So now that I've confused you, the best thing to do is research other people's builds, see what they've used, and see what the outcome is. Dyno performance, drag strip times, etc. Also do some research on cylinder head flow numbers and learn what they mean. learn the different styles of SBF cylinder heads and how they affect performance. How intake and cam come into play. There is an infinite amount of information on this subject, you just gotta dive in and start researching.

Easiest way is look at low to mid lift flow numbers. Your "street car" isn't going to spend a lot of time at high lift. And any of the 165-185cc heads will flow tons of air. General rule of thumb about bigger cc heads needing revs for power production is only half right. IMO if you think your going to race it go with the biggest head you can get away with.