Detroit 12v92 swap project

Hi all, I'm planning out a project a factory two-axle Peterbilt 379, I'm going to be dropping in a 12v92t Detroit that came out of a fire truck according to the website, I'm going to put behind it an Eaton RTLO-22918B since I'm unsure if the factory 10 speed can handle the power. What bellhousing will I need? What clutch kit will I need? Looking at the listing for the Pete it indicates the Cummins in it is rated at 1,400 lb-ft, about 600~700 below the Detroit, would I want to swap differentials to one that will handle the power? Will the tach pickup for the NTC Cummins work with 12v92? I have a feeling I'll want to add a boost gauge and an EGT gauge, should I try and make the factory speedometer work or should I get a GPS sender? Will the factory air cleaners supply enough air for the engine? If not, will the factory mounts work with aftermarket ones that would flown enough air? Would it be worth the effort to plumb in a CO2 connection to shut it down in case of a runaway condition? Thanks in advance for the help.

 

What are going to be using it for, show truck, rat rod type of thing, or working it?

 

It's going to be a toy, I don't like to associate it with show trucks because I'm not a fan of show trucks as I feel like they lose the essence of what a truck should be, a work horse first and then a show piece. It's not going to be a work truck because I'd have a Volvo VNX for that, plus the Pete at some point had the fifth wheel assembly removed so I figure it'd make an interesting candidate for some wrenching

 

You are gonna need the 127 bbc long hood to get that v12 to fit. It uses the SAE#1 bell housing same as Cummins or the 8v71. Mounts may need to be found or fabricated. Rear diffs will handle the power. Not sure on the tach drive. I think the detroit 2 strokes run a different ratio than the Cummins. You will have to use a tach that has the right drive ratio. Can’t remember but I think Cummins is 1.5:1 and Detriot needs 2.0:1? Speedo will work you just need to get the matching sender for your trans, rear gear, and tire diamater choice.

 

Okay, as far as the hood goes would it be better to go with an aftermarket fiberglass one for the 127 BBC or should I try to find an original aluminum one? Where does the tach get the sender from, transmission shaft? Alternator reading? What?

 

Looking at the electrical side of this, is the system nominally run on 24 volts or just the starter circuit? What output is the alternator rated at?

 

As far as hood it’s up to you what you want to do. It’s your custom project so do what turns you on. Most of the tach drives I’ve seen come off the blower housing. 24v for starting only but you can convert to 12v.

 

Myself I'd convert to 12 volt. I hate those series-parallel switches.

If you're putting the long hood on it, prepare for a TON of work because you'll literally have to remount the cab further back on the frame.

 

What goes into a 12 volt conversion? As for remounting the cab I imagine the hardest part would be the weight as it does not seem light, how much would I be dealing with?

 

For the most part it'd be replacing the 24 volt started with a 12 volt one, removing the series-parallel switch, rewiring the batteries and running heavier gauge cables to the starter (12 volt starter will draw 2x the amperage as the 24 volt one will). I do not know if the control wiring for the starter solenoid is 12 or 24 volt though.

Loaded cab is definitely not light. I'd have to estimate it being at least 2,000 lbs. More with the sleeper. I've got an old KW A-model cab gutted right down to the shell and I think 3 strong people could lift and move it.