i just aquired a GMC 3500HD with a 6.5 with a busted crank. i have a DT466 with the inline pump turned way up, and an Allison MT654CR, and i am wondering how bad this swap will be, i know the radiator will have to go inside the core support, and the intercooler may find itself on the front bumper, along with a body lift and a hood scoop to fit the engine. any suggestions? should i scrap the idea and try to find something smaller such as the 12v Cummins?

 

It just depends how much work you really want to do. You could alter the firewall to help get it in there as well. It would be a tight fit but you could do it. I know I had to remove 6-8 inches out of a 76 chevy cab to get a 466 behind the radiator and that truck had a 3" body lift already.

 

i was looking at the firewall and the only issue i can see is that the heater box is right there, can i cut off that whole section of the heater box and just loose heat to the floor of the truck, or is there other parts such as the heater core and a/c core in the middle section.

 

Yeah you could do that. I saw a 91 ford F-350 the guy moved the heater to under the cab and he said it worked great. It also had a 466 in it with a body lift as well.

 

will fit but there is a lot of work infront of you keep us undated on the project

 

It's a great idea. Since you have the 466 already, take all the critical measurements, and even strip the truck down to a cab & frame. It may be easier to lower the cab on to the engine.
What's been done on the 466? Just fuel rate? More? Think the Allison is gonna hold it?

 

i turned the fuel rate all of the way up and adjusted the starwheel, supposedly the timing was advanced and the delivery valves and injectors were messed with before i got it, but i have no way to verify these mods. what else can be done to this pump? i want around 500 to 600 hp and think with twins and the current mods i can get there, i also plan on propane and water methanol. i am not sure how long that allison is going to hold up to the extra power, i talked to the guy at the allison dealer and he said the tranny was only good to 300 hp 800ft lbs, but that is with a 46k lb truck. is there anything i can do to beef up this transmission? i cant find anything on the net for heavier duty parts without going to something bigger such as the HT750.

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the other thing is that the truck is the HD so its a 16000 gvw, dana 80 rear, almost 5" tubes, and has a factory body lift and filler panel below the grille. looking at the frame next to a chevy 3500 non hd shows that it will support the weight and stress of the engine, the frame is factory plated with 5/16 and is beefier by far than the 1 ton. the front axle is a drop I beam which makes the swap simpler and will support the weight, although i do want to make it a 4x4 with a dana 70 4" tube front, later.

if anyone needs 6.5 parts other than the bottom end, like wiring harnesses a rebuilt automatic or anthing im pulling out let me know.

 

I am thinking about a similar swap/build, with a 8.3 cummins and an mt654 or I know of an ht740. If you look at the specs on the tranny it says its good for 450hp/1250tq, with a gvw rating of 130000lbs.... My thoughts are that it would hold up just fine because you are not putting the stain on it trying to move 60 tons. The fact that your truck would be so much lighter also allows it to spin the wheels when you really get on it.

 

As far as beefing up the Allison, there's a place in Ill or Ohio that does performance Allison, I lost all their info. The only other one to consider would be an MD3060, that way you can have overdrive, or even double OD.
The pump has lots of room to grow. For what it's got done, you need to take just the pump to an injection shop and have them up the cc. Oregon Fuel Injection is a good place to try, and quite helpful. They can help get the most from your pump, but 600hp will need 13mm plunger & barrrellls. Does the engine run at all now, like on a test stand?

 

I have a freightliner fl70 wiht the 8.3 and the allison MD3060 (double overdrive) and man is it awesome... the truck weighs 22k, and it hauls