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I finally inherited my grandpa's 1996 two-door Chevy Tahoe with the 6.5L turbo diesel. Out of ignorance and excitement, I went ahead and ordered two new complete heads for the engine. I very much want to keep the truck and use it, because I am sentimental about this vehicle and would like to get it running as soon as possible. The current 6.5 has close to 250k miles on it, but I noticed that it's possible to do a 6.5L to 6.2L conversion.
In your opinion, would dropping in a lowmileage 6.2L be a better bet, or would I be better suited rebuilding the current 6.5? A Cummins swap is also on the table, but that would throw the idea of a quick solution off the table. Thank you for your time.
Cortland Woodard Via e-mail
Hi Cortland,
If you can locate a good used 6.2L diesel engine, yes, it's entirely possible to use that in place of the original 6.5—at least the short block.
If you could locate a good-condition 6.2L engine (possibly ex-military), you would need to keep the original (or replacements) 6.5L cylinder heads due to differences in the injector mounting angles. You would also need to maintain the 1996's aluminum front cover, harmonic damper and timing set to keep the electronic systems working. Depending on the year of the 6.2, you might also need to use the oil feed port nearer to the oil filter to supply pressurized oil for the turbocharger. The 6.2L diesel engines were never factory turbocharged, so they did not incorporate a turbo oil feed port near the front of the engine, where you find them on the 6.5L engines.
However, before doing anything, I suggest you have the original engine carefully examined to determine whether it's rebuildable. If it is, that route would likely be the best choice for you.
A 12-valve, all-mechanical 5.9L Cummins engine is just too heavy for the 1500 series chassis, and it would be a step backward compared to your original V-8 6.5L diesel engine, in terms of cost and drivability. For simplicity, parts availability and help with repairing what you have, I recommend sticking with the 6.2L/6.5L engine. Good luck!