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98 2500 6.5

Staufferjake said:
Is 94 6.5 diesel compatible with the motor mounts on my 98 that had a 454. And will stock Trans bolt up
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With enough time/money anything is possible. Details. We need more details. 2wd or 4wd from donor to receiving vehicle. What do you mean by "bolt up" for stock transmission? Will they physically mate or are they electrically compatible also? Frame/motor mount-wise, yes the the two will interchange, use new motor mounts, though. You are also swapping across OBD-I and OBD-II computer systems doing this. And most importantly, WHY would you want to do something like this? Just rebuild the 454, you'll be much better off.
 
I would love to replace 454 but don't have motor it couldn't have been original I'm not sure how it ran as long as it did. As for the swap "bolt up" is "mate" and I guess all aspects on Trans being compatible. The 6.5 come with computer and harness I need for it
 
The 6.5 uses the standard Chevy bolt pattern on the bell housing and the 454 torque converter for the 4L80E is the same, but that is the LEAST of your worries. This is WAY beyond a "drop it in, bolt it together, plug the harnesses together and go" swap. WAY beyond. Starting with the chassis fuel system being totally different between gasser and diesel. Different fuel tanks, lift pump, lines, filter system and NOT compatible/interchangeable, you can NOT run the diesel off of the gasser system. Oh, and the '94 6.5 OBD-I system is NOT backwards compatible into the '98 gasser truck's OBD-II system. Totally different sensors/types, engine and body harnesses and computers. Oh, and the '94 Diesel computer will NOT be able to run the '98 4L80E, either, without some reprogramming that isn't available, either.

You'll be dollars, man-hours and headaches ahead to just drop a used, parts yard 454/7.4L motor into the '98 and run that. This is NOT a 350 for a 454 swap across model years by any means. People, much to their regret, try to do what you want to attempt thinking "Oh, this'll be easy, it's Chevy to Chevy(GM) across model years, everything will just bolt together and plug in, no problem." and then find out all the things they never knew about the major differences the hard, expensive and frustrating way and wind up with two non-running trucks out of it.
 
Do you have emissions where you live? Going Diesel from Gasoline generally not allowed.

Have you pulled the pan off the 6.5 Diesel and checked for mains cracks? You may as well put new rings in it, head gaskets and head bolts. Checking the heads for cracks along the way. Know what you have to work with before you go through this much pain and expense to drop it in. Sadly lots of these 6.2/6.5 engines are walking zombies due to cracking: Run great till they don't because the mains crack out clean out of the block.
 
@Staufferjake. Wise choice to stick with 454 because of expense, and I am a 6.5 fan.
Listing parts for sale in the other section is probably a better choice to conversion.

Your best option on what is directly compatible and the sourcing for you- google search “auto salvage yards” in your area. They have a detailed listing of what years work and usually know inventory and pricing all around you.

I wish there was a section in the forum titled conversion with sub headings of gas to diesel; diesel to gas; diesel to diesel (like cummins into gm body).

Then we could just give a link and say “read these attempts”. And if people that get it done part way would what worked and what didn’t. Then they could even list the entire mess for sale at the end of each attempt, as well as all the parts in the for sale section-

Those who understand and are willing to invest the $4000-$8,000 it takes to do that if they can fabricate EVERYTHING themselves- and shops charge $50,000-$100,000 per truck to make this happen.
 
Welcome to the forum @Staufferjake

the only reasonable attempt to convert gasser to diesel I would offer is to keep the entire ecm, harness , 6.5 engine, tranny going into the gasser truck. then swapping out all of the fuel system including the tank. once that is done, it's swapping the instrument cluster and dash wire harness over. essentially making the 94 look like the 98 on the surface. the problem is the area you live may require emission where the truck would never pass due to it's 98 classification having stricter testing plus certain areas make it illegal to remove any emission parts or modify them. only way to get beyond that is using the 94 frame and body and maybe just swapping out dash and interior from the 98.

interior swaps do give some of these older rigs a nice touch :)
 
The problem with that is that the 94 and 98 interiors do not swap either way, going earlier into later or later into earlier. Between 95 and 96 GM changed the floor pan stampings, the interior door frame stampings and the dash mounting brackets/points. Nothing interchanges. Seats, door panels, dashes/instrument clusters/controls - nothing. Even the interior wiring harnesses are different. It's like when they went from OBD-I to OBD-II they went whole hog and changed everything but the major exterior body panel stampings at the same time to effectively get another five years out of the "fresh" GMT-400 platform with its updated interior design.
 
Staufferjake said:
So if I stick with the 454 does it have to be in the 95-98 Era or will older motors work because of the obd issue
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As long as you can install the correct sensors/senders on it for the 98's computer, no problem. It may just be as simple as bolting on and using the newer intake manifold on the older motor so that you can use the correct throttlebody and MAP sensor for the computer to "see". You get what I'm saying? Or using the later, OBD-II three wire sender that will screw into the hole the earlier, OBD-I sender screwed into on the older motor you're using. This isn't specific, it's just examples of things you may have to do to get the older replacement motor to work in the newer vehicle, understand? Like using all the accessory brackets and the alternator and A/C compressor for the 98 on the donor motor.
 
most of the GM blocks 454 in your case should have all the same ports on the block and heads. the only difference is depending on how old of a block you get it might have a place to mount a mechanical fuel pump. that can be blocked off easily. they sell block off plates for that. the most important part is to strip the engine that will be going into your truck of all sensors and then pull yours on a stand side by side. transfer ALL sensors and engine accessories including the intake over to your "new" engine before installing. after that, it will be a downhill slide to the finish line were you'll be on the road in no time!

of course you will want new water pump, pulleys and tensioners. also while your in there, check and replace the timing chain. you might also need to swap over the timing cover from the old engine too.
 
@Staufferjake that was an example of a possible difference, NOT an actual change you'd have to make, when switching between computer generations. Like @Will L. said above, switch it ALL over from one engine to another. IF you have to replace a bad sensor or sender from on the 98, use ONLY genuine AC Delco electrical parts, DO NOT use parts store branded or generic parts - ESPECIALLY NOT AutoZone - as many of those "new" parts are bad/fail out of the box with bad/no readings.
 
Ok sound like this one should work it's a 1990 that I'm thinking in buying. My truck doesn't have a motor to start so will be buying new everything as for sensor and everything else for a 98 and install to donor motor
 
While engine is out and on the stand, install a new rear main seal on the cranking shaft too.
I always install new timing chain/sprockets, fromt seal and coolant pump too.
If the engine has some miles on it it would be worth it to pull rocker covers and install new valve stem/guide seals and rocker cover gaskets.
Doimg a gasket freshen up and timing set allows the engine to go a lot more miles without having issues.
 
Staufferjake said:
I wanna thank you all for the input on everything for my build
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It would be nice if You could start a thread about the progress of this project.
Then there would be a place where We could watch, throw in hints and really get You confused. 😖😹😹😹
Just kidding on the confused part. You could post in questions and get some speedy answers to solve any mysteries.
 
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