Studied the 8.3L in the truck more yesterday. I need to get lucky on 3 things for this to work, which "should" go OK from a visual:
1. Front mount carry-over from 8.3L to ISL, looks to be same 4 bolt pattern, 2 per side at an angle into front of engine.
2. Would like to use the flywheel housing that came with the ISL and puts the starter on the driver side, as this frees up passenger side block clearance to use the factory block mounted coolant filter on the ISL. Not a requirement, just a want, but side mount pad locations would need to be same pattern and location as the 8.3L. Or, as long as the bolt pattern on the back of the block is the same, I could simply re-use my 8.3L flywheel housing onto the ISL engine. Plenty of room on the driver side for a starter though if I can use the ISL flywheel housing it came with. Also need to be hopeful that an auto trans flywheel housing is also compatible with a manual trans configuration. Looks like it, but not 100% sure until we try it.
3. Our 8.3L oil pans have a special curved depression in them to allow clearance for front axle up travel in suspension. I would either need the 8.3L pan to bolt up to the ISL, or it looks like the rear sump ISL pan may fit and work, especially if I move the engine/trans back just slightly. Front prop shaft clearance to transmission gets closer of course, but that may or may not be in jeopardy already, TBD on install.
Easy to say I should have checked these first, but not that easy to recognize without having visual access to both engines. None are deal-breakers yet.
Looks like whoever gets my stock 8.3L gets the entire drivetrain, everything from the fan blade to the output yolk of the Allison, including the external trans cooler and spin on trans filter/lines/hoses, as it will all be getting extracted. Will even be including the 110A Delco alternator and high capacity enhanced Sanden A/C compressor, as the ISL uses a more modern accessory mounting.
