What size are they? couldn't find anything when I searched for them. Were they 310cc?

Same as the SR20VE grey top "333cc"

Ohh thought they were smaller, I rem seeing people who had SR20VE's switching from the SR20VE ecu to the SR16 and the car running leaner.

An SR20VE will run leaner with an SR16VE ECU because it's injecting the amount of fuel it figures is necessary for a 1.6L, not a 2.0L. I too tried switching the cams to see if it changed, but the ECU just isn't right for the engine. I ran a back-to-back dyno comparison w/ wideband on:

-stock SR20VE w/ 20VE ECU
-stock SR20VE w/ 16VE ECU
-SR20VE w/ SR16 cams and 16VE ECU
-SR20VE w/ SR16 cams and 20VE ECU
-SR20VE w/ SR16 cams and custom ECU tune

the AFR on the SR20VE was reasonably stable with both cams, but I was able to get it closer with the custom ECU tune. However, the AFR for the SR16 ECU is just too lean before 5400rpm and way to rich after that (15:1 and then 12:1). Cams made little difference. The ignition map was also less than ideal, as it's configured for a TOTALLY different rod ratio and displacement. The timing is important because the ECU's are programmed to combust a certain amount of fuel to create X amount of pressure in a given amount of time. These are all variables that are different between the engines.

So even though the stock 20VE ECU could only rev to 7200rpm, it made more power than the 16VE ECU in that whole range. Though I will fully accept that you may be able to get a higher peak HP number with the 16VE ECU, for whatever that is worth (not much). I will also admit that it is much more fun to rap the car up to 8k RPM's.