I don't know who makes it but the 300ZX transmission is very strong and has been proven to hold well over 500hp reliably.
That's just a little unfair. The first DOHC engine was released in 1912, only ten years after the first pushrod engine. So DOHCs are almost a century old themselves. Also, when you say boat anchor, that conjures up images of something heavy weight to most people. Thing is, pushrod engines are usually more compact and are typically lighter weight, not to mention having less parasitic valvetrain losses. Also, an LS1 is obviously a more high-tech engine than either the VH or 1UZ, as it was designed quite a bit later than either of those engines, and it was intended as a high performance engine from the outset. It has coil-on-plug ignition, a very flexible stock ECU, and extremely good heads(even normal LS1 heads, which are by no means the best of the breed, flow somewhere around 290cfm if I'm not mistaken. Feel free to correct me if I'm wrong.)
I'm not trying to knock the VH, but the LS1 is clearly the better performance engine in almost every concievable way. It's smaller, lighter, makes more power and torque, produces less emissions and uses less fuel, has a larger, cheaper aftermarket, and if you ask me, looks better with that beautiful intake manifold, especially if you have the red Corvette fuel rail covers on it. The only thing the DOHC V8s have on it is they can rev higher. That may be important depending on your needs.