You're going to have to figure out what you want...max power, fuel efficiency, replicate a stock '71 340, etc. Most people don't step down in cams so its either a stock like cam or one step up assuming no other engine or powertrain upgrades. The e420322 might be ok but will obviously be pushing the limit for a stock car with 9:1 compression (approx). I'm sure others will chime in with recommendations for a stock 340. Perhaps there are better grinds out there and there lots of cam threads here. I just built a stockish 340 with an Oregon Cams '68 340 4 speed replica cam. It is torquey and sounds nice cruising. Based on the first 100 miles I doubt the fuel economy is any good but I don't expect any of them will be great. It idles a little too smooth for my liking and vacuum is on the low side. If I had to pick another cam and wanted to keep the cost down I might go back to Oregon Cams and get a recommendation from them. I expect the specs wouldn't be far off the e420322.