Actually more like .500 lift is the consensus. I believe the W31 and W30 cams were that lift due to racing rules at the time. The 204/214 cam should do. Buy the cheapest version you can find, get a quality timing set, like the Cloyes Billet 9 way and degree that cam.
Retro-Fit Hydraulic Roller. Very strong increase in low RPM torque and power. Works well with OEM style injection, great inboard/outboard marine cam for economy and sking. ;Advertised Duration (Int/Exh): 262/270 ;Duration @ .050 (Int/Exh): 211/219 ;
THey're $400 on eBay I got those HyLift Johson lifters for a decent price when they were released last year from a vendor on ROP it looks like I paid $180 shipped even though they're going for $280 on eBay. Then you gotta buy the button from OPP. I'm modeling my build off of cutlassefi's "C Head 403" and even that "budget" engine had the roller cam.
Although I got the BossHog 48402 only cost me $177.56 after Summit Price Matched one that I found on eBay for that price! It's a 24-2800 advertised stall speed. I got it in the car now with the 307 mated to a JEGS 60306 TH200-4R Performance Transmission that was $1350 on Jegs eBay store. I think it's the absolute cheapest hotrod 2004r combo you can possibly find.
Also the roller rockers from a SBF can be used instead of the expensive Olds HS rockers (although if you're patient finding a used set is possibles; that's what I am gonna run).