I know what I want for my Mav is a 331, I'm not qualified to get into the 347 vs. 331 debate but this article has some good info on the differences. I do know that a shorter stroke creates and engine that likes to rev, and that's what I like in a light car. http://www.fordmuscle.com/archives/2002/04/331/
My personal 'thing' between the 331 and 347 is the level of clearancing and tight fit of the 347 internals vs the 331. It's just me, and probably because I would tend to build my own engine, as opposed to buying a short block. I would feel more comfortable building a 331. Therefore I tend to favor a 331. Not that I have anything against someone suggesting a 347 or building their own.:Handshake I would also add that I am a believer in having as much rod ratio as possible... The 347 just falls short of the minimum rod ratio for my personal taste. I know we could argue this point all day, so I won't. It's just my personal taste.
Let Common Sense Prevail Hi All, So, everyone seems to agree that some sort of 302 based motor makes the most sense for a street driven high performance Maverick. It fits, and at 347 cubic inches it will produce an easy 425 to 450 horsepower with a robust and broad torque curve. Some favor the 331 storker for a variety of reasons, but ultimately with all things being equal the 347 should be knocking out an extra twenty five horsepower. Wear factor differences between the travel in a 331/347 should be minimal. And, only if using the Brodex 23 degree heads or beyond are you going to see any up shift in the peak power point with the shorter stroke and then its going to be minimal. But if you are going to destroke the engine down below 302 and use CFE heads and sheet metal intake with full competition prep, then things are different - $10,000+ different. So let common sense prevail. You can get an easy 300 horsepower with bolt ons for the 302 or go with a bad boy 347. Regards, David P.S. - I said sense not fun or a challenge. To those who want to jam a bigger engine in, I say congratulations to the 351 users, and I have seen one to die for 460 in a Maverick.
the displacement difference between the 331 and the 347 dones not mean that you will get aprox 25 more hp. a engine is an air pump no matter what the displacement is the powe is determined by how much air it can move. so if you run the same intake, heads, cam and exhast on both engines the only significant difference in dyno sheets will the the rpm that the power is made at.
When I was building my Maverick (before it was totaled) a number of years ago! I was using a stock crank, and block, Crower I-beam rods, and Venolia 11.5:1 pistons. Trick Flow Heads (Track Heat) w/ a real nice port job and bowl work, and a Victor Jr, and Crane 1.7 roller rockers. (I sold everything above for $1600.00, like a dumb a$$!!!). The cam was going to be a custom grind, and a then what ever ignition system. That was going to be my daily driver!!!
Silly Me Hi All, It really never occurred to me that one would not optimize their engine build to suit the displacement of the engine. And, while I do not totally agree with all of Bryant's statement quoted above. The bottom line is that built to the same level as an engine for a hot street car, I'll stand by my statement that the 302/347 ought to yield an extra twenty five horsepower over the 302/331. And, as to rod to stroke ratio, I will follow the Comp Eliminator racers who would at a maximum get 322 cubic inches out of a Dart Boss 302 bored to 4.125 inches. For a street engine, all things being equal, the all saw, "There is no replacement for displacement," still stands in my humble opinion. Regards, David
