[Lapkritis]

Yes, they might deal with differential thermal expansion coefficients between jug and stud, but there are plenty of ways to deal effectively with stud/case issues.

Other than case savers, simply never driving the car or thermal loading the entire engine when stored such as Formula 1 teams do, what are these other ways? Praying and crossing fingers doesn't count. Neither do rabbits foot key chains. Or Horse shoes.

Now you are interested, which is fine as an abstract matter, but in this case Henry actually did quantify his views - he had measured temperatures on the smaller bore iron cylinders,

Show me the data. Simply saying 20-30% near the top of the cylinder is hotter than the rest is like saying that the fridge is colder in the freezer half. Of course it is hotter up there as that is where the flame is. Such a statement is not a measurement. I'm sure there's plenty of folks with running cars at the track. Put an infrared thermometer on an aluminum jug and aluminum head at a specific point and report back with the temperatures. Ideally, take pictures or video to increase credibility. I will do the same with my project as I think that everyone will learn something rather than trusting "once upon a time" stories.

and didn't like what he found if the intention was to raise the HP and so create more heat. And his logic in extrapolating this to larger bores seems pretty convincing.

Logic is a tricky thing as is extrapolating. Consider for a moment what happens when you run high hp on aluminum cylinders. The same flame temperature is present and the same EGT flows through the ports of the head. The difference is the aluminum cylinders warp before iron or steel would. They had to add a liner to increase strength. In HP terms, Nikasil is not a significant power adder... a turbo charger is a power adder. More on this later... essentially what I want to open your mind to is outside the restrictive box of what you've been advised by engine builders and folks for years. Sure, lots of builders including Henry have done a great job to this point. If Steve Jobs worked on Porsche engines... do you think he would have stopped with the fastener/case saver? Of course not. If he did we would still be talking on bag phones.

And head cooling is pretty important. Porsche found that it couldn't keep the head temps viable with 4 valves per cylinder without water cooling. The change from air and 2 valves to water and 4 has led to an increase in attainable race motor power per liter from 110 hp to 170 with the current DFI motors.

I'm afraid that is a different topic. We don't know the cylinder head temps for this application yet but we will this summer and that I promise you. I don't have anything to hide; I plan to run the car essentially in stock form with the billet upper valve covers and turbo lowers to start; it has SSI headers already. If my monitoring shows head temperatures that exceed comparable stock 911 numbers with aluminum cylinders then I will be milling all 4 valve covers flat and welding on 2" tall heat sink blade over the entire cover before retesting. If tests still show unsatisfactory CHT then I will add CO2 burst circuits to both banks of cylinder heads for WOT operation. I'm not adding neon under glow, big rims or a booming stereo. I understand this may not be to taste for the pedigree folks but what's the point of having a pure bred looking dog if it's dead.

Now none of this should discourage you from trying iron cylinders, and measuring things, and so on. Maybe conventional wisdom and weight of authority have it wrong,

Don't worry about me being discouraged... the exact opposite happens each time someone tells me "new guy thinks he knows something we don't". That game I like to play is NIGYYSOB. I look forward to proving folks wrong; it's how we make progress. Someone always has to be wrong... normally they're smart enough to keep it to themselves to avoid any public embarassment.

It's not that conventional wisdom is wrong. I'm not here to cure cancer or to win the 24hrs of Lemans. I've been around long enough to hear people who've been working in high performance shops for the same amount of time as Henry tell everyone they meet that you can't safely run a long-duration, high lift cam with a turbo charger. It'll blow up they said. It'll flame out from blow-through they said. You'll have high EGT they said. Someone finally had the balls to put one in and it made 150hp more at the same exact boost pressure. It only took 15 years to shatter that myth in the VR6 Turbo community. Retailers were suddenly scrambling to rebrand their high-lift, high-duration all motor cams as turbo cams... Techtonics 288 cams sold out and were commanding a premium of MSRP. That cam set then went 208mph in a street car at the Texas mile. Go figure.

and there will be a boom in finding junkyard T iron cylinders. I once had a 2.5 race motor built (originally) by none other than Grady Clay. It had 88mm iron cylinders with a 66mm crank. Pretty peppy motor, and the rather small valved/ported heads didn't seem to be in distress. But it got sacrificed for its sand cast case for a 2.7, which was a lot peppier yet. I've still got the Ps, Cs, and heads, which I suppose I ought to try to sell as I'm not going to use them.

I don't see any Porsche folks serious about longevity (myself included) buying junkyard cylinders. I'd rather have brand new Chinese and then get my local pal to run them through the shop for a few bucks. They all have Saudi Arabia corsing through their veins anyway... who cares if it works.