A few years ago, Jay Brown published a nice book called the FE Intake Comparo or something like that. I bought that book. So, a nice book with all the data proving the point (cast iron vs. alloy) would be fanatastic.
Also, if the result is 15-30 HP difference then I'd argue "WTF" that's it? All this chatter for a statistically insignificant amount of HP? I'd assert HP would/should be eliminated as a benefit or positive when choosing a cast iron block over alloy.
Honestly, we have maybe a dozen owners here of alloy blocks that don't have any reliability issues and assuming the extra HP is 15-30, which to me is insignificant, then the only reasons you would chose a cast iron block is: a) price, b) you want your Cobra replica to have a vintage block, maybe correctly dated, for "originality" purposes, ridiculous and nonsensical as that concept may be and c) the desire to add 125 lbs for no apparent reason.
