302 or 347
 

Ok Ive been wanting a new motor for my 90gt's tired 140k plus mile monster. I got quoted 3k for a 302 with forged internals and install, Well the dude has a nice 347 with new balanced crank and all new JE forged internals ready to go and is tellin me 1k more so for 4k I get a 347 with a balanced crank and all new internals installed what do you guys think about that cause I'm new to the motor building world, the reason someone is doin it for me is cause I have no space or time to do it myself.

:o 347

347

I dream very good, very wet dreams about getting a 347. If my motor would only blow up so I had a good excuse to part with so much money. Sadly, this 302 is far too strong and stubborn. Hell it's got 147,000 miles un-rebuilt and it doesn't leak or burn a single drop of oil. It's truly amazing. So in other words...push the extra $1000! Not only for your own enjoyment, but so at car shows when people go "302?", you can say "347", and see the look of awe and amazement on their faces. :D

Your not gonna put the E7's on the 347 are you?

For a grand more I would go with the 347 all the way baby.

Later,

heads
 

if u go with the 347, u really need a good set of heads. Ur stock e7's will choke it out, or so I have been told.
Ryan

I have new gt40-ps which he gave a full port job to along with a TFS street heat upper and lower intake, stainless headers, 65mm TB new mass air and a NOS 5115 dry kit :-)

347

well then
 

stuff the 347 in there, I doubt u will ever say "I wish I did not have so much power"...but if you don't go with the 347, u might say "wish I did have a little more power, or alot!!"
Ryan

on the 347 + E7 issue: A friend of mine has E7's on his 342 and the car is way faster than it should be if the stock heads really do indeed "choke" the stroker. Its my opinion that the smaller valves of the stock heads increase velocity, and you pick up lots of low end torque. His car is a rocket out of the hole, but doesnt pull up top like my Heads cam intake 306.

In my personal opinion, go with a 331 or even a 342 but not a 347. The reason being you want to stay with a 4 inch bore if you can. Also, the advantage of the 331 is that the oil ring does not intersect the wrist pin, a common cause of short engine life and compression loss in the bigger 347 strokers. Some companies claimed to have solved this, but I dont put much stock in it. The 331 has a shorter stroke for better rod angle, and a larger piston skirt. A 331 WILL last longer and make about the same power, no question about it.

e7's
 

I have no doubts that the 347 pulls hard out of the hole with stock heads, just makes sense that a stock head will not feed the bigger engine properly at higher rpms. I believe he said he has aftermarket heads, so this will not be an issue for him.
Ryan

The heads are gt40-ps with a full port job

If its a daily driver i would suggest a 331 :D

MYTH......

sn95gt19: I am good friends with a reputible engine builder/tuner who builds many Renegade motors. From what he's seen over the 25 years he's been in the business is that maybe the 3rd ring theory is a myth, but 347's cause accelerated wear on the cylinders. I've seen some of them and after a year or so the cylinders are all marked/scratched up. This wasn't one instance either, he told me he's seen it 3 times. Now if this were my motor, I would choose a 347 for a weekend/strip car, and a 331 for a street/strip car. I was going to build a 331 myself but decided to step it up to the Windsor block. So my bottom line is I believe 347 are more of a race motor that is going to be freshen up every once in awhile, as opposed to a street motor that will be driven 100k+ miles before being worked on. And 93GTDIN, a 331 is a 3.25 stroke with a 4.030 bore, I think you're thinking of a 327 if you want to stay with the stock 4.000 bore, but I definately agree with you and a 331 will last longer than a 347. ~Brian

we have 5 people in our "crew" (if thats what you want to call it) that have 5.4 rod, 3.4 crank 347's, and 2 331's all of which have never had a problem AT ALL with the piston "side loading" on the cylinder wall.

your reputable engine builder has seen 3-347's go bad....any ford dealership IM SURE has replaced more than 3 factory motors under warranty.

which by what you are saying.......the 347 is more reliable than a factory 302?

everytime this comes up, there are always people who think both ways. but in my opinion people emphasize the VERY FEW 347 casualties way too much, take in to consideration that:

FORD REPLACES FACTORY MOTORS, MORE OFTEN THAN THE AFTERMARKET CONSUMER REPLACES 347'S, im sure there are more 302's than 347's out there but im sure the percentage of replacement is the same if not less for a 347

there is only 1 problem with a 347: that is there is less "meat" on the top of the piston, which makes it weaker for use with "BIG" power adders.

I'm sorry I didnt mention that, this car is gonna be a daily driver, it will see the highway 5 times a week and mostly be drivin on the street. My mechanic mentioned a 347 cause he already had one and the internals, but I'm just looking for a nice motor with decent power that will last me +100k miles without to much maintence, something durable for a daily so now the question is 331 or 347? And the biggest power adder is gonna be a dry shot of nos 100hp and thats gonna be very rarley at the track if I even choose to install the system, other then that its just gonna be your basic bolt ons, maybe a year or two down the line a small super charger like 5psi

sounds like you need a 331

the bottome line is, myth or not, why risk the 10 extra cubes on a daily driver?

read the whole thread????

scrapala: if your are just building something really mild i would just stick with a 302, or maybe a 306, and spend your money on a good set of heads. afr 185's:D