Your gonna love that setup!!! So here is the scoop on Carbs, for good throttle response you want smaller, for High RPM wide open throttle you go bigger. Your PerfRPM setup already says you want power across the RPM range 2500-5500 so this decision is made, not its time to match the carb to the system. On my motor (same as yours) I run a 650 DP which pulls hard from 2500 to the relatively conservative 6000 RPM chip in the Rev Limiter since I cannot afford to blow this motor and the cam is rolling off by 6k. A lot of folks will SWEAR run big as will bolt on and a dyno run will show good numbers with a big carb because you floor it and the air flows unrestricted and unmodulated through the RPM range. Works great on the drag strip. However, on the street or in an Autocross / race situation, you are modulating the throttle constantly in the mid ranges and a big carb is just not as responsive since the air flow speeds are slower with huge bores. Smaller bores have higher air speeds which keeps the gas atomized in the mid range so a wide open punch is immediately felt due to the speed of the air flow.
Key to all of this is your MAXIMUM RPM, if you plan to be running at 8K, go bigger e.g. 650 to 750. There is a large contingent on this site that will swear a 750 is needed on a 351. I had both and liked the 650 for Autocross. Didn't really notice much difference on the street, but remember, I chip at an admittedly conservative 6k. I would start with the 600 since you have it and during your break-in, it will be just fine. It is possible it will roll off at 6500 but if you don't spend a lot of time there it should give great throttle response. From there, see if you have any Muscle car buddies that have other carbs you can borrow and try. Watch your tailpipes if they get very light in color as it could be running lean which can burn a piston, you may have to rejet. Speaking of which, While you are doing all of this, its a good time to add a Air Fuel mixture gauge which will tell you how your mixture is doing. I wish I had one and folks that have 'em can dial in mixture across the RPM range including the accelerator pump and get it all right on a moving car which you cannot do on a dyno.
On Carbs, Holley is a go to carb for performance but frankly they are a PITA to set up correctly. For instance for years I didn't know the accelerator pump cam could be flipped around and give an more aggressive profile. I couldn't believe the difference, someone at the track mentioned it so we flipped it right there to try it. Because they are made for performance, virtually everything is adjustable and most people do not have the skill or tenacity to set one up correctly. Most of the alternatives are simpler in design and a nice alternative for a street / strip car. As I hear often on this site, just bolted it on and it was great.
Then there is the Vacuum Secondary vs mechanical decision. For an automatic the Vacuum is a go to because it responds to the RPMs and gives you what you need when the motor needs it. People with manuals tend to go with mechanical for better throttle response unless they are building a primarily street machine. Lots of learning to do to make an informed decision.
Good Luck...
ONe last thing, just in case it hasn't been covered, if you got the big 202 valves, it takes special pistons or a fly cut setup for 351s to divot the pistons to clear the big valves. I don't think its as much of an issue with 190s.
