a 347 is a 302 block, but its bored and stroked, so its no longer 5.0 litres of displacement...more like a 5.7ish. a 347 is by far not a task to do with a small budget. if you are going to do a stroker, yeah you can do it half ass, but stuff is going to break and it wont make all that much power, if you are going to do it right, its a good $6000+ for a reliable, powerful, professionally well built stroker. if you are talking best bang for the buck with potential to upgrade upon later, IMO id have to say a 351. minor stuff needed to swap, and alot of potential. your tranny and suspension is going to need to be upgraded regaurdless of what you do, because stock suspension can only safely handel so much, and your car will be very hard to control with all that power. id start with suspension first, then worry about motor and tranny. i have known a few too many people that get a kick ass stroker built, throw it in a stock 5.0 and crash the car within a week because the car is not setup correctly