help me pick a engine...

[wgpaintballer]

Hey whats up guys i got a couple ?'s im looking into a new setup for a winter project im looking at either a 351 of a 347.. what i like about the 351 is that i have more space to advance is my car ever becomes a strip only..one is if it has efi can it fit under my 4" cowl.. also i heard that some of the parts may rub my guessing headers possibly.. also what does it take to get a stock 351 in the high 300's low 400's? thanks all also down the road (tax return) i may be adding nitrous if that helps also i have a manual tranny if u need to kno that thanks