Tom, please do an apples to apples comparison before jumping on me, thanks. 1 3/4" LT's WILL make more and ARE needed on a decent 347. I've already talked to real people on this subject like Jay Allen
I asked the same exact question and he said 1 3/4". You know who he is, right? Fwiw I dont really race dynos like it seems you do but did you even both to look at the graph I posted of a guy with "huge" parts on his 347 making more torque at 3000 rpm than pop's makes at the peak? Or 40 MORE ft/lbs at 2700rpm? Happy new year 

then I want to go faster
then I wanted to go faster so heads, cam and intake. thought that would be enough