Camshaft Selection Information

I am working on gathering parts to rebuild a SB 340 (Bored 0.030"). I am not rolling in the dough but am trying to purchase the best parts that I think I can afford. This is for what I hope to be a pretty good (I realize that what I call pretty good is all relative) but in the 400-425 hp range, if possible. RPM Max, probably up around 6000-6200. Not sure on SCR but maybe around 10.5-10.75:1. Car is 4spd with 3.23:1 SureGrip. May change to 3.55:1.

I have purchased a new set of ProMaxx 171 aluminum heads from Jason Collins (Have their published flow chart), PRW stainless roller rocker set from (SwingingDart; Thanks), new RPM AirGap intake (Supposed to be shipped by Edelbrock this month???) and new Holly dual line 770 Street Avenger carb.

Engine not torn down yet to determine piston characteristic(s)/manufacturer, deck height but appear to be aftermarket as seen using a bore scope through plug hole. It has original iron J heads and intake manifold at this time.

Having said all of this, I am trying to gather all required information that is required in order to try to spec a good street-able camshaft. Originally looking at Comp Cams XE274H but not sure. I have been watching some of David Vizards videos mentioning his 128 rule. I know he has some kind of software program or spreadsheet of some kind that may take into account more factors that just valve dia and CID but I can't afford that kind of program for a one time build for a street ride. I noticed he also had different starting number for Ford vs Chevy and SB vs BB in the formulas. He doesn't sound too impressed with just calling into the cam manufacturer or using their cam card specs, but I may have mis-interpreted the dialogue.


What information would you gather prior to calling a cam manufacturer or selecting the camshaft on your own if you didn't know an engine builder with sophisticated software like Vizards'?

Thanks