Yeah, as Mike notes, the 1/48 B-29 with a Revell label is actually the Monogram kit.
The two companies went through a couple of acquisitions apiece from the late 70s up into the 90s, when they wound up in the same investment company's basket. The brands were merged, keeping the Revell brand but shutting down Revell's operations and focusing on Monogram's facility in Illinois. The merged company wound up rereleasing kits from either catalog under either label, along with kits produced under license. To further complicate the family tree, Revell's European office became Revell of Germany, but which is not related to the current brand of that name.
Scalemates is good, too, but remember that it's essentially a wiki, so the info there is only as good as the contributors. But you can join and add content, too.
The Monogram B-29 is a good kit, though some will criticize it, because it does reflect the state of the art in 1977. I built it when I was in junior high, and I still remember how amazed I was, at the kit, and at Shep Paine's diorama using the kit.
I have a couple in my stash but haven't found room for the finished models yet. Mine are original Monogram boxings; I prefer the older boxings, since the molds were still new, not worn.
Anyway, I look forward to seeing your build, whichever you choose.
A post-script....if you want to buy the Monogram kit, I would wait till you can find it for a reasonable price on the secondhand market. You might also find it in a retail store today. By "reasonable price", I mean $30 or less. But that's just me. I see the ones on eBay, with a seller asking ninety bucks or more, but know I can get it for much less. Or look for it at a show or at a club meeting, if you can. I got mine for ten apiece at our Region II show, along with a pair of Monogram C-47s, also ten apiece.
