Welcome aboard thirdgen.org.
It's not asking too many questions, although taking a breath every once in awhile would be nice (you know, using punctuation
), and some of your questions are answered in the V6 to V8 swap sticky in the top section of this forum.
Getting a 305 TPI on a 350 is generally simple enough, because they are basically the same engine externally. What matters is the year of the 305 and year of the 350. '87-up small block Chevys (you know, 305's and 350's) had the center two intake manifold mount bolts at 72 degrees instead of 90 degrees like the rest. Otherwise, a TPI swap is a matter of getting everything associated with the TPI from a donor car (TPI intake hardware, harness, sensors, ECM, hoses, throttle cables, etc.) and installing it all in your car.
4-bolt main 350's typically came in Corvettes and trucks. It generally isn't necessary to pay the extra cost of getting a 4-bolt for a TPI street engine.
The V6 T5 5-speed transmission is not a good choice for a V8 swap. The bellhousing doesn't fit, so you need to get a V8 bellhousing. The input shaft is a different size, so you have to do a "hybrid" clutch. The transmission is weak, so you'll have to baby it in order to get any kind of life out of it.
