A 347 has a better R/S ratio than a stock 400 smallblock shivy or even a 455 ponticrap. Both engines have a rep for reliability and I know of several 400 sbcs that get the crap revved out of them. So I don't think there is much of a reliability problem with a 347. Given the nature of a two-bolt 5.0 block. I think if you keep it at 6000 revs or less it definitley won't be a problem and for a street car using a hydraulic roller cam, combined with the stock lifters along with steel retainers/keepers and stainless valves. You wont be going much past 6000 rpm anyway.
Take a look at the kits if your interested. From a longevity standpoint I'd go for the kits that have a full ring land below the oil scraper. Then combine that with a hypereutectic piston (if non supercharged or nitroused) and that should prove satisfactory.
As for cam and heads it depends of what your looking for in power? 450 hp?
Figure it'll take at least 219 cfm per runner to accomodate that power level and on a street engine exhaust needs to flow about 75% of the intake or about 165 cfm.
As for intakes, the GT-40/Cobra flows in the neighborhood of 230 cfm. So that's right where you need it as far as flow. coupled to maybe a 70mm t-body.
An easy 400hp would be (might make a bit more than that), That's the torque approach. You could trade some low and mid range torque for a bit more power upstairs by going to a set of AFR 185cc heads. A Street heat manifold, Edelbrock Performer RPM and the like would net some more hp too. Mainly due to more balanced runner flow and runner designed to work with a higher reving engine.
347 c.i.d
AFR 165cc heads
GT-40/Cobra intake
70mm T-body
9.50:1 comp ratio
1-3/4 headers
Comp Cams XE282 hydraulic roller
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