SeventyMach1 said:
Well, I don't really know that, lol. But I just know that the rod ratios (angle of the connecting rods) are different. They're more "spread out" (or downward, if you will) on the 347's. In turn, the crank is pushing the rod at that angle .... pushing the piston into the side of the cylinder wall.
Yea i know how the argument goes so i wont try to start one
But i will say that a qualified engine builder can and will build a 347 that will run and last just as long as a 331 or a 306. This argument is fed by guys who build 347s who dont know what the hell they are doing....and the complaints obviously come from guys with problems. I've heard of a 306 being crap after 60 miles...but the rod ratio isnt blamed then is it? Nope, its the builder. But for some reason when 347's mess up, its the rod ratio and not the builder? And the funny part of all the threads about this argument is that its all "theory". Yes it will have "more" sidewall loading...but there has never been anything documented to prove that its makes a lick of difference. If the idea is so solid, why hasnt it been proven? Because its too hard to...too many other variables will come into play with an engine and how it wears before side loading does.
Every engine has its role into a specific combo and im sure you'll be happy with your choice! The key is the engine builder i think...not necessarily the engine u pick although obviously they both matter. It seems from what i have read and from what i have learned from talking to pros...the bigger the stroker kit, the tighter things get and the more IMPORTANT small details get. On a 306 you might get a way with a little laziness, just like a 351, but on a 347 or say 427, the builder better be on the top of his game so that the motor is right. After all the shortblock research i have done....i'll stick to having shortblocks assembled for me, lol, it gets too complicated and too critical. Filing rings is not something i would trust the average joe to do. Neither is boring a block. I've heard about how some shops cant even bore a straight cylinder, let alone file a ring correctly. These are the shops that the bad 306's and 347's come out of i think. If you went to a shop that is reputable and can actually perform the work(which it seems u found one
) then i dont think it would matter which shortblock you got as they would all be of the same quality and probably last just as long if treated equal. Besides, the performance and pushing our motors to the limits will wear the motor before the rod ratio.
Did ya know you could do a 347 with a 331 piston? Are you planning on revving the 331 any higher? Will it need a different gear than the 347? What are your goals for it? I know 1 thing guys like are going with 331's to rev them higher or to use in blown applications...both of which would cause more wear than a lower revving 347.
Its about the whole picture...not just the shortblock. It starts with the guy putting it together, then its the motor, then its the car, then its the gearing, then its the treatment of the whole thing as 1 unit.
Sorry for the rant