We knew what you were talking about...it's the same old saw one always hears when discussing 331's vs. 347's. Funny thing is, again that all comes down to the builder and the quality of parts more than any specific dimensions etc. For myself, I've never been involved with an oil burning 347. I also wouldn't build myself a 5.315" rod 347 (by the way...the pin isn't 'too close' to the oil rings...it's inside them...and causes no issues). 5.4" rod only for me. Additionally, I don't know what makes you believe that a .085" difference in where the pin intersects the pin boss on the pistons has anything to do with the thickness of the piston crown itself. There's plenty of distance between the top of the pin and the underside of the crown on my Probe 1.09" compression height pistons.

Now...I also want to say knuckless...PLEASE don't take these replies as swipes at you!! You seem to be one of the victims of this misinformation that I was talking about earlier. Your 'to be different' reasoning for building your motor is a good one!! It's also the only valid one I've read so far. For a street only build your 331 will meet your goals admirably. Thing is...so would a 347 =D. So, for you...it's a matter of personal preferance. Just don't base that preferance on any abnormal wear issues you've read about, because if built properly (like any other engine), those issues are simply myths.

Just trying to help...

Cris

 

thanks for the help

 

Mind if I take both sides of the issue?

These myths have some truth to them, but the issues are easy enough to MOSTLY completely overcome.

I think the differences between a 331 or 347 are small enough when put into the context of our "weekend cars" to allow for snap decissions.....

If a person is looking for "reliability" "stick to stock", (and the stock power output that goes along with stock).

A simple rule of thumb is that increased performance = less reliability and longevity...

There are exceptions for sure, but rest assured, if you have a 289, a 302, a 331, or a 347 that is making north of 450 HP, it's longevity and reliability, (on average), WILL be LESS THAN a STOCK engine.

Of course this rule only applies to cars that are driven, and I am sure someone will chime in about their 650 HP SBF that turns low 9s at the drag strip every weekend and still lasted just short of 250,000 miles......

But, there is no free lunch.

 

Like I said earlier in the thread and as you know Cris, the fact of the matter is this whole rumor of oil burning was caused by a faulty piston design when the 347 kits were released from various manufactures. I've seen these motors first hand, and now that is a thing of the past, but it never ceases to amaze me the amount of misinformation still out there on them. I know what Mahle did to correct this is add a support for the oil ring.

The funny thing was, I thought this myth was close to extinct until I worked the All Ford Nationals a few weeks ago.....

 

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thanks a lot all of this really helped a lot. Everyone that posted taught me a little something i didn't know.