347 stroker life expectency

[allrightmike]

 A friend is looking at a Cobra replica purchase and asked me about the 347 situation. My opinion is that the combination is a bit less than ideal so before advising him I attempted to do a bit of research. Google search revels mostly anecdotal info from Mustang forums or people selling engine parts, but an almost total lack of input from actual engine builders with experience in this area. Particularly the 331 vs 347 comparison for engine life and oil consumption. Comments anyone?

[475fetoploader]

That's a tough platform to argue with, because it's proven itself.  The only thing I really dislike is the connecting rod angle.  Short deck height with the stroker crank in my mind would try to shove the piston through the wall.  However there's a mountain of them running around.  Obviously we would all like to see an F.E.

[blykins]

I've built more 347's/363's than I can remember.   I have no qualms with the 347 and have only built one 331 in my lifetime as an engine builder.   I did a 347 for a local bracket racer.  He ran it for 8 years in a local 7.50 1/8th mile class, while driving it on the street.   I took it in for a freshen-up and the cylinders/pistons looked great. 

One of my journalist friends from Muscle Mustangs & Fast Fords had a Fox Mustang with a 347 in it.  Had 100k miles on it. 

You can only believe about 10% of the stuff you read on the internet, but Randy Gillis did tell me that Probe Pistons really messed up the design for the pistons when the 347's started coming out.  Led to lots of oil consumption.  You just don't see that anymore.

[allrightmike]

Thanks guys for the input. My primary concern with the 347 setup is or was with the rod angularity but it sounds as though it works. I'm with you as to we'd rather have the FE. We looked at one Cobra advertised as a 427 but no matter how I looked with my flash light you couldn't see the cross bolts. We had them put the car on the hoist and sure enough...no cross bolts! Probably a 428 7 liter with a med. riser two four intake. It idled so smooth! Who ever bolted it together was not a FE man...oil leaks every where.

[blykins]

I do a lot of Cobra engines as 428’s.  They were in a lot of street Cobras.  PI engines.

[Rory428]

I ran a 331 for a few years, and currently have been racing a "big bore" 347 for 6 years in my Fairmont drag car. It runs 10.0s at 133 mph in the 1/4 mile, at the end of every race season, I do a compression test, and leak down test, and after 5 years of 64-6600 RPM clutch dumps, and 7000 RPM shifts, every cylinder is 215-220 psi, and the worst cylinder leaked at 4%. So far, so good.

[allrightmike]

You can't argue with that kind of performance (331). I built a Shelby speck. GT350H a few years ago and used an Eagle 331 stroker assy in it. Had Trick Flow heads, Blue Thunder intake, Comp. solid cam, dual point dis. and a real K code carb. That engine was a pure joy, always eager to buzz 7000 pulling all the way!