Wow... if I may ask, what pre-1968 car that came with an I-8 are you considering fitting this engine into? Are you planning to use an automatic or manual transmission?
I don't know the width of the 2JZ-GE, 1JZ-GTE or 2JZ-GTE offhand but the 2JZ-GTE's in stock fully dressed form are not exactly narrow. 2JZ-GE's are slightly less wide at least on the passenger side due to not having the complex sequential turbo hardware.
GTE engines have a single exhaust exit from the passenger side of the engine. From there the vehicle model that used one of these engine might have had a single or dual exhaust under the chassis.
I've seen plenty of engine bays with everything from Jeep 4.0L I-6's to the old Ford OHV 170cid-250cid I-6's. The Toyota JZ engines only being DOHC does make it a bit wider than anything that was SOHC or OHV from the 60's-80's. Offhand I am not sure if 26" is enough to clear.
You can set up the 2JZ engines with more simplified engine control systems, yes. The stock ECU will want to see various emission sensors, ABS, airbags, etc. but you can use an aftermarket standalone ECU also to avoid all of that without employing workarounds. I would recommend making your own revised fuse box and relay setup.
Now I will say that the 2JZ-GE VVT-i is a very good engine and very similar to the earlier non-vvt versions but if you are planning to turbocharge it you will need to factor in rebuilding with stronger rods, pistons, rings and a thicker head gasket. 1992-1997 2JZ-GE Non-VVTi engines came with the same strong rods, pistons and rings as GTE turbo engines aside from their non-turbo pistons being 10.0:1 and the head gasket being very thin to make up the 10.0:1 compression. 1JZ-GTE Non-VVT's had 8.5:1 compression w/twin parallel turbos, 1JZ-GTE VVT-i's had 9.0:1 compression w/single turbo and 2JZ-GTE's had 8.5:1 with twin sequential turbos.
Especially for an application like yours (if turbocharging is even applicable at all) you'll most likely be using a single turbo no matter which JZ engine you use as a basis.
1998-2005 2JZ-GE VVT-i engines have even higher compression and a still good but different cylinder head design and the aforementioned weaker factory rods, pistons and rings that must be changed for boost applications.
All GTE engines had strong rods, pistons and rings from the early Non-VVT and VVT versions.
So you know, your horsepower from any stock non-turbo 2JZ-GE engine is 215-225 hp / 210 ft-lbs. For some vehicles 225hp can be just right and the engines love to rev and are a lot of fun... but just to address this point upfront, there isn't much financial sense in modifying them for more naturally aspirated power, only turbocharging.
I am excited to hear about this former inline-eight car you are considering for a 2JZ swap!
Last edited by KahnBB6; 02-15-17 at 08:07 PM.