I run a 300-36 Holley intake on the 305 in my S-10 with no complaints.
As far as cam choice goes, once you clear about 260* of advertised duration you are going to start loosing bottom end power. In the 218* @ .050" range you will start to out run the flow capabilities of the stock heads. Anymore duration and you lost bottom end without being able to regain it in the top.
I run a solid flat tappet cam that specs: 258/270, 219/229, .456/.479, 114*lsa This cam has a smooth idle, pulls 19" of vacuum at 600rpm, and gets 21 MPG with a 200-4R and 3.73 gears. It also pulls hard from idle-5500 rpm. Last trip to the track, the truck consistently ran 76mph in the 1/8 with a best of 76.72mph.
The cam DoubleVision chose is a good one if you are going with Summits cheap line. Power will be in the 1200-4600 range with a smooth idle.Vacuum will be just under 18 1/2" at idle. My fuel mileage was 20.
For reference, I also ran a Crane Blueprint series 300hp/327 cam. Power dropped like a rock at 4200. 19 1/4" vacuum and 21 mpg. Trap speed for the Crane was in the 70mph range. The Summit cam ran a best of 72.67mph in the 1/8. The Summit cam also had the slowest 60ft time by .04sec. Dan