Heads are one area where you really get what you pay for. A good set of aftermarket heads and matching cam can add 50-100 hp to a mild small block 302. For example, in my sig I run Edelbrock Performer RPMs. Are they the best aluminum heads? No. But they're a good step up over stock iron and I got em for a decent price. A step above the RPMs are the AFR 165s & 185s and 170 cc Trick Flow Twisted Wedges and they run about $300-400 more than I paid for my RPMs. Every once in a while Summit Racing, who owns Trick Flow, will have the TWs on sale. Last year they had em on sale for $999, which is a little less than I paid for my RPMs. Great buy. There's a bunch of aftermarket heads available, do a little research. I would suggest staying away from the Chinese parts like ProComp. There's a reason they only cost half as much as American made heads.
Here's an idea of the difference in wear rates for a 302, a 331 and a 347: In a 302 running at 3000 rpms for one hour, one piston will have traveled 90,000 FEET. (6" x 3" x 3000 x 60 / 12 ) In a 331 (6.5" per one revolution), it will have traveled 97,500 ft. In a 347(6.8"), it will have traveled 102,600 ft. The bearing wear will be pretty much the same, the only difference being the larger motors exerting greater force on the bearing. They will also exert greater stress on the block itself. As I said before, how long any motor lasts depends on how it's run and how it's cared for, that's the only thing that's not a constant here and cannot be calculated. Remove that from the equation and the wear on the pistons, rings and walls are pretty much set in stone.
So the 347 piston travels 14% farther than the 302's. You're saying if the 302 lasts 150,000 miles the 347 will only last 129,000 miles. Not that I believe that's an accurrate assessment. If your lubrication system is up to snuff the wear will be negligible anyway. Nowadays you see engines with 100,000+ miles on them and the cylinders still show the crosshatch.
The reduced cylinder wear in today's factory motors is a direct result of the factory tightening piston to bore clearances and the use of low tension piston rings. Then there's the vastly improved cooling systems that allow faster warmups and narrower operating temperatures, this also reduces block wear. Most of these factors will not be present in 90& of the instances we're discussing here. So what I've been saying here still holds true, if everything else remains equal, the lifespan of a 347 will be less than that of a 331 or 302. Whether an engine does or not, is an answer no one can answer as no two engines and their owners are the same, someone saying that this is a myth, well that argument just doesn't hold water.
The original discussion was the difference between a 331 and a 347, no mention was made about a 302 until now. The lifespan difference between a 331 and a 347 will most definitely be negligible and will be more a factor of overall hp and how much abuse it sees. I've build 331's that didn't las as long as 347's and i've built 347's that gave up before the 331. All were due to something else and the specificic "size" of the motor had nothing to do with it. It simply boils down to, just build what you want and run it. Eventually they all break.
Now that's the most intelligent statement in this whole thread! No offense meant towards other posters.
cometgt, you are trying so hard to say you never said anything about getting more miles on a smaller stroker but you are the one who originally brought up getting maybe 2000 miles more. nice try, trying to be a smart-ass.
Trust me, my ass is so smart, I can sit on a block of ice cream and tell you what flavor it is! You can read it any way you want, I know the meaning that i was trying to convey when I typed it. However, something was lost in translation and nobody got it. Well, maybe a few got it. I'm done w/ this thread, good luck w/ your motor.
This thread got me to thinking... and I was just wondering if Anyone has ever known of a stroker motor (any size) that actually has 150,000 + miles on it ? ....
I average about 3,000 miles a year on my car. It would take me 50 years to reach 150,000 mile. Even my daily driver would take 11 1/2 years to reach that.
That would take me about a hundred years to hit that mileage. Seriously. Wear and tear on a 331vs347 is irrelevant to myself. It just doesnt get enough mileage to worry about either engine due to wear. I think this would apply to many of us.
Lets see -- 5000 miles on the Mav in 1.5 years so far. At that rate when mine reaches 150,000 miles I'll be 118 years old. I'd probably have to move to Florida to keep my driver's license.
