Hi 1bad89, i've been researching on upgrading my 350 as well. I can't decide if 180's or 195's would be best. From what I can gather 195's might be too big for a 350 unless it is a high rever with holleystealth ram intake. 180's have very similar flow numbers compared to 195's. 195's start to flow more at very high lifts. 180's would produce lots of torque with smaller chamber and be good fit for a strong 350 TPI setup. Supposively port velocity between the two is similar but the 180's have a great exhaust to intake ratio. I would go with 180's. They still flow like crazy! Check out this link
http://www.thirdgen.org/techboard/tp...195-heads.html (AFR 180 or 195 heads?)
Fuel injector size is determined upon engine horsepower (see link bottom of page)
http://www.rceng.com/technical.aspx
Using 380 HP requires 30lb injectors. I forget how much stock 48mm and 52mm throttle bodies flow but 58 is overkill even on most 383's.
I've read some good things about Comp Cam XFI 268 Hydraulic roller camshaft. It has very aggressive lift characteristics and yields good lower end and mid power. Also with lobe seperation of 113 degress it is good for tuning. Anything less than 112 I believe is hard to tune for a TPI engine. A few guys here have it on 350's and are making around 400hp. Any more intake duration than 268 degrees I think lowers vacumn pressure and affects power brakes, etc (that's what gives you choppy idle).
http://www.jegs.com/i/Comp-Cams/249/12-466-8/10002/-1
Once you figure your build out, I would speak with a few stall converter manufacturers to see what they recommend. You will also need to build up transmission and rear end for that much power. Either way you go, your 350 will be a mean street machine!