IMO, do a combination on a 2UZFE block.
Your 93 SC400 is probably making 175rwhp/185rwtq.
The non-vvti Tundra 2UZFE is 4.66 liters (4.7 advertised) with an iron block, 94mm bore and 84mm stroke and rated 240hp/315tq.
Use your stock heads and intake. This will raise compression to 11.5 to 1 due to the increase in bore and stroke. You want to port both your heads and the intake manifold. I am not certain what octane you would need for this compression. This is based on 51.8cc combustion chamber volume. You can do some minor chamber work to get the ratio down. 54cc chambers gets you 11 to 1. 56cc gets you 10.75. 10.75 should work fine on 93 octane R+M/2 (USA spec)
The end result should be a complete factory appearance externally that will deliver probably 60 more rwtq (dyno re-calculated, much more in reality) and 30rwhp or possibly more.
Some other options included looking for 1995-1997 LS400 or Celsior exhaust manifolds and heat shields. The are dual tube vs single tube and have EGR connections.
Mild increases in cam timing.
Increasing the bore from 94mm to 97mm taking displacement from 4.66 liters to 4.97 liters.
With a better intake manifold and exhaust with tuning this combination is probably capable of 250-260rwhp and similar torque.
Your 93 SC400 is probably making 175rwhp/185rwtq.
The non-vvti Tundra 2UZFE is 4.66 liters (4.7 advertised) with an iron block, 94mm bore and 84mm stroke and rated 240hp/315tq.
Use your stock heads and intake. This will raise compression to 11.5 to 1 due to the increase in bore and stroke. You want to port both your heads and the intake manifold. I am not certain what octane you would need for this compression. This is based on 51.8cc combustion chamber volume. You can do some minor chamber work to get the ratio down. 54cc chambers gets you 11 to 1. 56cc gets you 10.75. 10.75 should work fine on 93 octane R+M/2 (USA spec)
The end result should be a complete factory appearance externally that will deliver probably 60 more rwtq (dyno re-calculated, much more in reality) and 30rwhp or possibly more.
Some other options included looking for 1995-1997 LS400 or Celsior exhaust manifolds and heat shields. The are dual tube vs single tube and have EGR connections.
Mild increases in cam timing.
Increasing the bore from 94mm to 97mm taking displacement from 4.66 liters to 4.97 liters.
With a better intake manifold and exhaust with tuning this combination is probably capable of 250-260rwhp and similar torque.