dude he's on an arduino forum talking about modding his "old" 80s car (my arduino design is getting scrapped for some dedicated ICs and a Raspi going into my 73 VW, but I digress). Lets not talk about what is sensible or reasonable ok? I also am finishing a nixie tube dash display....
anyways, a real simple pressure guage to use are the MPX5100s, they take 5v (steal it off the arduino, its regulator will drop the cars 12 to what you need, but will get warm) and will spit out reasonable voltage for your ADC. Just go thru the choices and pick the right pressure range, I have been using them for low pressure stuff and know they make a 3psi max, 15 psi max, and 100 psi max guages, there may be more inbetween. However I doubt they are fuel proof, but if you isolate the fuel so only vapor makes it to the sensor, you might make it work. a length of hose, and vertical placement could let you get by for a while. the sensor is slightly protected on the inside, and they are only about 16 bucks iirc. Also you can nab a vacuum guage from the same sensor line, and check MAP or any other fun stuff. I plan on using it to compare fuel pressure to manifold vacuum, as thats how the old VWs enriched under load.
however if you do settle on the perfect sensor, let me know! thats more money than I want to spend at 90 bucks cause I have a bunch of other sensors going in (accel, cylinder head temp, oil temp, oil pressure) and fuel pressure is just a fun but useless value to know. I have a analog guage for tune ups, you don't need it while driving, but need is niether here nor there.