The first listing, the crank is not an Eagle catalog part number. I have heard of factory defects (returns and such) that are repaired, then sold quietly from Eagle. Ohio Crank also does this. There's nothing wrong with it, but that "030" at the end tells me it might be already ground undersize. I'd avoid it.
The second listing Is a good Eagle crank, and they are right with Ross not listing falt tops. But...Diamond does. Ross has dished for street, or domes for high compression. You can buy Diamonds for about the same as Ross plus the modification, and they are a better piston IMO.
There is more to them than just bolting them together. With a small block, head choice is very important. A modern chamber, Like Edelbrock's Magnum style, works very well with Ross's dished version for a pump gas engine. Flat tops can also be used for this, but I'd run LA style RPMs with them for ease of install. The block's bores have to be notched to clear the rods(rod bolt nuts, to be exact), the correct iwndage tray needs to be used (for the 4" arm...the Milodon is the best one for this), and main studs should be used. ARP lists a 12pt set..get them. One stud needs to be modified to clear the oil pump, but the smaller nut will clear everything better.
With any kit not containing a Callies crank, I would make a couple assumptions. First, every part should be inspected, using a micrometer. I've found several of various brands that are machined barely adequately. Crank journals that are "in spec", but on the smaller side. Main journals with taper exceeding .0005". Rod journals with the oil hole chamfer that runs almost all the way accross the bearing surfaces. Snouts that are too small to fit the press fit the balancer needs..etc. They generally need nothing, but, if you dont look, you may have issues. In worst case, you can either pay to send it back and get another one to check over, or you can pay to have it machined correctly, albeit to a smaller (.010) journal size. The rods suffer from pin bushings not finish honed to proper size, overall length variences, and the most common, the big ends not beign round after cycling the bolts a few times. The bushing and length issues are not a big deal(length being a difference of .004" between 8 rods), but the big ends can be messy. Once cycled, you must torque them to correct spec for the bolt(or measure stretch) and then check for roundness. If they are way out, replace them. Trying to correct and redo them is hard, because the caps are doweled. Minor honing can be done easy to fix them. Most times, that's all you need to do, and adds about $100 to the machining bill. I'm not really trusting, so I have all my stuff balanced at my shop. I've seen what some places call "balanced", and it's not what my shop beleives...lol. think of using a bubble balancer for a wheel and tire, vs a high speed spin balancer. Some machine shops use the same equipment they have had for 40 years. The results usually show it, if it's checked on a computerized balancer fixture.
The 408/416 is a killer package in any form, you will be happy with it, just take the time (and expense) of doing it right once.
