x3. tbi heads have the same number of bolts as the old heads, center holes are on different angles, votecs only have 8. No centers.
vortec's stomp tbi heads anyday.
now with that said, either is fine.
tbi, you're gonna HAVE to have a custom chip burned to change cams, or any real mods. PERIOD.
Now with that said, get the 350, rebuild it, do what you want to it, and continue to drive and use the truck while doing so. That wouldn't be possible if you build the 305, it'd be down until you were done.
1 peice rms and 2 piece really makes NO difference, just run the flexplate/flywheel that matches the motor.
If you want to get tech on it you can use 305 heads on the 350 and depending on the casting, due to the cc and such it can raise compression ratio, I say some because some casting numbers came on 305's and 350's and have the larger cc, which is lower comprssion and wouldn't bump it up. Now the typical 305 heads like 58cc and such them will bump it up, bad thing is they don't flow that great to help back up the higher compression. Sort of a win lose deal IMO.
I say get some real vortec heads and put on either one you build to use, then run a 4bbl intake with an adapter plate if you want tbi.
