Replace 6.5 L diesel with 454 ?

[Scott Royse]

Can a 6.5 be replaced with a 454 in 1993 with a 4L80-E transmission. If so where can I go to get info about changing out?

[AndyL]

:(

[cruzer]

What's wrong w/the diesel engine? I ask, because, I might be intrested in it.

Ken

[markrinker]

Yes you can replace it with a 454, or a 350, or an inline-6, or Corvette LS-6 for that matter.

It will not be an easy task, and will likely cost more than repairing/replacing what is wrong with your diesel.

Here's why:

1) Entire fuel system from the tank forward will have to be replaced as well.
2) Entire wiring harness and computer will have to be replaced with one compatible to the generation of 454 you intend to swap in. Get ready for some fun 'bridging' that harness to the remaining accessories.
3) The 4L80E will need a new torque converter and new black box to match the computer you select to control engine management for the 454. (If you have gone 'old school' (non-computerized) with the 454, you'll likely need to go 'old school' with the tranny as well, aka turbo-400.

My advice: If you don't want to monkey with the diesel fix, sell the truck to someone that does and go buy a truck with a 454 already in it.

Just my .02 worth.

[Arlie]

Here's a post I found somewhere (?) a while back that sheds some additional light on the subject. If you had access to a 454 truck for cheap and lots of time plus patience maybe...


The 6.2 and 6.5 motors bolt right up in place of the 350 and 454 and vice versa. What you need to do is get a torque converter and flexplate for a 454(the diesel trannies have different converters and flexplates, but everything else with the tranny is the same). You will need a wiring harness out of another truck of the same year that was equipped with a 454, all of the brackets, a power steering pump, and an A/C compressor. First, you should disconnect the A/C lines and CAP THEM OFF IMMEDIATELY, if you do not cap them off, you will need to replace the entire a/c system($2000). Next, simply unplug all the wires and vacuum lines and pull the motor out. Third step is to replace the wiring harness, you can get by functionally on the original diesel harness, but you will have a lot of loose wires that will need to be taken to a shop and clipped(6 hours of labor), so I think it would be easiest to replace the wiring harness altogether. Next, drop in the 454, put the brackets and water pump, alternator, etc. on. I should note that you will have to get a power steering pump that was made for a 454 with a hydraulic brake system(a very rare option for gas motors, but every diesel has this brake system), because a conventional vacuum brake booster system will not work on this truck(at least not safely) without replacing the pedal assembly(5 hours labor at shop). The radiator that the diesel came with is much bigger(and in the world of radiators size is everything), but requires 2 inch hoses, whereas the 454 has 1.5 inch hoses, so you need to either 1. find a shop that will fabricate your hoses to be 2" at one end and 1.5" at the other end 2. replace the radiator with a gas engine radiator, or 3. spend an hour forcing the stock hoses onto the radiator(physically possible but very difficult, trust me). Finally, get rid of one of the batteries because gas engines use one battery only, and siphon the fuel tank(s) and fill them with premium and a couple bottles of octane booster to help get rid of that diesel crap. That's about all there is to it. You should listen to me because I'm not just one of those internet geeks who knows everything about everything; I've actually done this exact same conversion, only with a 1986 pickup, and if you were to call auto shops and ask about this you would get a different response from each shop, most of which have not and will not do this conversion. Good luck.

Also, my 1986 required no computer work, but I don't know about a '95, so you might want to play it safe and gut every last piece of wiring, vacuum lines, and computer module out of the donor rig.

[mklein]

I did the exact opposite swap this past summer. My 95 suburban had a TBI 454 in it, and I changed it over to a mechanical 6.5. My 454 already had hydroboost brakes, so that was cake. Same pump and lines. Physically, the engine will use the same mounts, just take the ones off the 6.5 and bolt them on the 454. For 95, both engines shared the same torque converter. I checked the part numbers using parts imager, and they were the same. So no biggie there. I used the existing wiring harness, as there was already a real estate for a TPS sensor, ECT sensor, etc. I mounted a TCM where the ECM had been, and spliced in the TCM's to use the existing wiring harness. For controlling the trans, this is pretty straight forward, down to most of the wiring colors and circuit numbers. As stated earlier, you will need to modify the fuel system, especially if you plan on using fuel injection. If you are using a carb, you shouldn't have too much of a problem eliminating the old diesel fuel pump (whether mechanical or inline electric), and using a engine mounted pump for the 454. Anyhow, good luck!

[moondoggie]

Good Day!

You'll also need a MUCH larger fuel tank, so you can go more than 100 miles without having to fill up. :D

Kidding aside, good luck on your project.

Blessings!

Brian Johnson, #5044

[Herman_Bolger]

We just sold a 454 truck and bought our first diesel 6.5. you could not give me another 454, and i've had lots of them. We came back from Texas this spring with a 15500lb load, had to stop every 150-180 km, about 110-125 mi for fuel. I'll keep the 6.5 thanks. But good luck if you are doing the conversion. We have a lot of exp. with cam and other mods that will make it just as good as a 6.5