holy shit... why do people keep sending this guy engines... there are a few around here that still swear by him and will tell you how busy he is and that you should just wait patiently until you get it back because nothing out there can compare, but it is complete horseshit... tons of equally talented and better builders out there that can turn motors around in less than 2 weeks.
you want the whole thing to be open like they are from the factory or are you interested in one with cabinets across the front, double insulated, a/c unit on the roof, and beds that fold up against the walls?
70 is very doable with the right combination of parts... this is a pump gas 350 that was ported in 2003, so I'm sure there has been much more learned in the past decade.
If you decide to take sprinklerman up on his offer to come help, I'd like to come hang out and learn too since I don't know dick about dome design or porting, but love to learn. If not, sprink, you can hit me up when you are in Arlington... we can head over to Redneck Heaven and have a couple beers and look at the trashy chicks lol.