Hey guys...long time since I have been on. I have to get a few words in here. My buddy was attacked by someone who stuck his own foot in his mouth...time for fun
Ok. You said that it is all in the setup...apparently you don't know how to set a car up. I had a friend with a 347 that had the same problems. I ran mine on the dyno before I put my blower on it and made 380 rwhp. Your mph is indicating around 275-285 rwhp...gears do have something to do with your times though. Here is what I see wrong.
Bcam in a 347? Not the best choice
GT-40's in a 347? Bad choice too...ok if ported really good
Good Intake
What fuel system?
What exhaust?
You should run around 113-115 with a properly set up stroker. I say with your heads, cam, and exhaust you MIGHT get 110-111 max. They say you theoredically get 1 hp per cube if the block were all that was changed. So I say MAX you should make 330 rwhp with that combo. My buddy had a 347 with the Holley SystemMax2(better Intake, crappy cam, similar heads) and ran 107-108's with 3.73's. His car was jacked though.