RustyRatRod's Guide To Hot Rod Bliss

As others have said, the stock 68 to 73 340 cam is very good. You can tell by it's sound it is a performance cam. It Idles well, comes on like a freight train about 3,000 rpm, and will pull above 6,000 rpm and get there quick. The 68 manual transmission cam is a step bigger. I have no personal experience with that cam other than a friends 68 4 speed Fastback Barracuda. The 340 cam was upgraded some time in the 70's? for a faster rate, more duration at .050" lift. When I rebuilt a 273, 318, 340, or 360 engines for friends street cars I would use the standard 68-73 340 cam. Never a complaint. All that said, can you use a newer grind with about the same duration? Yes. On lift, the thing to remember is that stockish heads max flow is around .450 lift. In my opinion, I will rarely go to a higher lift than that. If you have heads that more flow at higher lifts, then you can adjust your cam to take advantage of that. However everything, changes at that point. I use factory positive valve seals and new or used 340 single valve springs, no special machining or parts. The bottom line is, I run street cars that go anywhere, last forever, are pretty fast and still get good gas mileage. A cam is the heart of your engine. Honestly decide what you want long term. Feel free to talk to cam grinders, custom grinds are not that expensive.