road car cam for my 318

I'm with @ch1ll on this one. I always recommend calling your chosen manufacturer (or several if you want options) to see what they suggest. If their website has a downloadable cam recommendation form, print it and fill out as much as you know before you call. Those guys design cams for a living. They'll provide better results than crowdsourcing, whether it's a custom grind or something they regularly stock.

After that, look into your timing. As the Borscht Belt comedians used to say, "Timing is everything." At part-throttle cruise you want a ton of it (often 50+ degrees). The more timing it likes, the more power it makes. The more power it makes, the less you have to open the throttle to maintain the same speed. Juggling and adjusting vacuum-advance canisters can work wonders here without affecting your base and centrifugal timing.

With economy being of primary concern, your car is also a spectacular candidate for a 340/360 ThermoQuad. It's hard to beat a good spread-bore when your foot's not in it.