The 2jz-ge (NA) is a phenomenal power plant on a budget. It has been proven a million and one times. Of course the piston tops, as previously stated, are different in order to increase compression, but essentially the same in every other way including strength. Here are the to know's about going NA-T.
The basic differences between the GE and GTE (not comparing either VVTI editions):
-Most obvious difference to anyone familiar with engines is the TURBOS. The GE has none, thats what the 'T' in GTE means.
-Another is the style of intake manifold, the GE has a manifold developed for more torque development in the lower-part of the rpm band vs the GTE's short runner type. The GE doesn't have more torque; its just that it develops more than it would if it had a GTE-style intake manifold.
-Compression, the GE runs a 10:1 compression ratio and the GTE runs a 8.5:1 compression ratio. The differences are obtained through a thicker headgasket (.2mm for GE vs 1.6mm for GTE) and lower compression pistons on the GTE. The higher compression allows the GE motor to make the most of its power since it lacks turbos to begin with.
-Injectors and Airflow sensors, the GE runs 330cc top-feed high impedance Denso-style injectors and uses a Karman Vortex air-metering sensor to read how much air volume is being injested. The GTE runs 540cc side-feed low impedance injectors (though uses a resistor pak to raise the impedance for the ECU's sake)... measured through a hotwire MAF sensor. The GE's airflow restriction is around 450hp from the stock AFM and the GTE is around 650-700hp depending on several factors.
-The exhaust manifold and intake manifolds port spacing and studs are completely different and will not work with one another unless some machining is involved with the manifolds themselves. There are people who have successfully grafted the upper part of the GTE intake manifold onto the lower part of the GE manifold.
-The GE motor runs a distributor-based ignition system with spark plug wires and a single coil. The GTE runs coil-on-plug ignition with individual coils for every plug. The distributor gets in the way sometimes of the turbo intake pipe
These are just motor differences, there are many little others such as oil squirters, oil feed/return lines, transmissions, etc.
Now onto Similarities:
Both the GE and GTE bottom ends are VERY strong. The only difference being the pistons themselves. Thats right, the rods and crankshaft are the SAME parts!!! The 2jz motor itself was DESIGNED to be turbocharged from the beginning and is built VERY strongly from the factory. No one yet knows the limits of a GE setup, though there are several 1000whp setups on the GTE with the stock bottom-end. Dave H uses a GE motor and ran a 9sec 1/4 mile time with the stock GE block ( a spare 220k mile motor to be specific!)
All in all, it is very doubtful that you will need to build your motor when designing a NA-T setup unless you're gunning for ridiculous amounts of power. The stock cams are roughly the SAME.
As far as the 6 speed, look up R-154. It came factory in all turbo supras from 87-92. It's a bullet proof 5 speed tranny which many have chosen for drag strip success.
Okay I'm pooped