331 or 347

speedfreak5.0

New Member
Sep 18, 2003
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ohio
Well ive decided that the motor is coming out of the stang this winter and getting redone, not sure to go with the 331 or 347 stroker kits. what would be the best one to go with and still be a dependable engine? Im planning on running a motorsports X cam with afr 185 or canfield heads, and either the edelbrock or the new bbk intake manifolds.
 
Wow another 331 vs 347 thread. It's been all of about 8-hours since one of them has popped up. :rolleyes:

Someone should really make a sticky in regards to this topic. Along with 3.73's Vs 4:10's.

The best advice I can give you is to use the search button. This subject has been covered several dozen time....probably in the last month.
 
Easy now gearbanger. Yes, there are tons of these threads, but be nice :D

anyway, to the topic. Gear banger is correct though. The best way that your going to pick the right one is to do the homework on each one. Research which one works out best for that person, even IM or email a person with a 331 or 347.

My vote: 331.. because i have one.
 
Nahhh, I wasn't harping on the kid, just think we need a big, bright red SEARCH button that comes out and slaps you when you ask certain repetative questions. Waiting for a short tube vs long tube header question next. :)

For the record, I'm all for the 331 too. Just because N8 has one. :D
 
347 because its FREE hp. 331 vs 347 are the same price, NO reason to fear a 347, but sadly many fall to internet myths. Its ALL in the build and machine work! Im planning a 347 now :) 16 extra cubes is a good 15-20hp (more depending on combo) why anyone wouldnt want that amount of hp for free is beyond me.
 
N8Miller said:
do you agree with greenlx that it will make 20 more hp on a 347?

Sort of, 347's make more trq in lower rpms (like 15 more then 331), BUT the 331 makes a 40 hp gain in higher rpms (i think its 40, but you can correct me, its from the 331 WAYS TO WASTE AN LS1, PART 2)

but my vote 331, after all the problems i've heard with the 347, and the 331 is AWESOME with power adders
 
FiveLtrRiceEatr said:
Sort of, 347's make more trq in lower rpms (like 15 more then 331), BUT the 331 makes a 40 hp gain in higher rpms (i think its 40, but you can correct me, its from the 331 WAYS TO WASTE AN LS1, PART 2)

but my vote 331, after all the problems i've heard with the 347, and the 331 is AWESOME with power adders

I see that you read MMFF...... :rolleyes:

I would love to see a non-biased dyno.... with my own eyes.
 
Again, I'll stress the improved "Volumetric Efficiency" with the 331 over the 347. It's similar to the comparison when you add a power adder to a 4.6L mod motor vs. a 5.0L. PI heads in comparison don't flow much better than a set of GT-40's when you're stacking them up against some the heavy breathing small block cylinder heads available now a days, but given the same level of CFM's entering the engine, the mod motor will endure a better cylinder fill and more powerful charge than the larger displacement 302. The end result being more efficient and complete fill and combustion cycle and more power! A 347 might lead to a little more torque going the N/A route, but the comparison is very small. The rod ratio debate is somewhat valid, but pretty negligible unless you’re leaning on either engine very hard. Both would yield decent longevity with reasonable power estimates.
 
I say a 331 because I have heard very little negative stuff about them. The 347 is still a good choice but a lot of them seem to have the oil consumption problem simply because of where a lot of the kits like to put the oil control ring - that is too close to the wrist pin.

As for power difference, it's like comparing a 5.0 to a 5.8, they make power slightly different. An engine with a larger stroke (the 347) will likely develope higher torque levels whereas the engine with the shorter stroke (the 331) will likely make more horsepower given equal equipment. Take it for what it's worth.....
 
87'GTstang said:
I say a 331 because I have heard very little negative stuff about them. The 347 is still a good choice but a lot of them seem to have the oil consumption problem simply because of where a lot of the kits like to put the oil control ring - that is too close to the wrist pin.

As for power difference, it's like comparing a 5.0 to a 5.8, they make power slightly different. An engine with a larger stroke (the 347) will likely develope higher torque levels whereas the engine with the shorter stroke (the 331) will likely make more horsepower given equal equipment. Take it for what it's worth.....

Just to let you know, out of the 3 347's my family has owned, none of them ate any oil to make it noticable. In fact, my 302 probably eats more. The oil consumption problem is a myth that really needs to be put to rest.
 
Go big or go home.. although there really isn't much difference between either.

I'd go with a brand new short block and some forged goodies though if you plan on racing that motor hard. Or if you have money just buy a nice long block and just bolt on to that.

OT: What's the displacement of a 347? [ie. how many litres?]