I ran across some old pics while searching for something else this last weekend and finally got around to scanning them.
Curious who here might understand what they’re looking at and then how much information they can glean from just the pics…
Kinda looks like a manual transmission with an overdrive on the back.
That hose from front to back is interesting.
Edit:
The sump pans on the bottom suggest it’s not manual.
More like an auto without a torque converter or fluid coupling.
The fine finish suggests it’s military, like a trans for a tank?
Transmission for a semi? The two linked transmissions would provide a lot of gear ratios.
A pair of GM Turbo 400 transmissions sharing the pump of the front trans. Could be a 9 speed transmission but I’d guess the front box shifts 1st,2nd,3rd and then the rear shifts 1,2,3 for a 5 speed automatic transmission.
Vintage GM 4 speed hydramatic? I have owned and driven 2 but that was a long time ago.
Sure what it looks like.
You agreed with 3 or 4 possibilities, Kevin. Which one do you mean?
Mustang man has it right. Its a trans I built years ago for drag racing a chevelle. A 5 speed set up semi automatic w/reverse ordered manual valve bodies. Front section has pump and only forward gears. Rear section has full gear set but no pump. Sumps from back pan. Pump pickup tube runs inside the hose connecting two pans together. 5 forward gears, 3 reverse. I use two quicksilver ratcheting shifters to control it. All gears freewheel except 5th so if you let up on gas it just coasts. Meant to save engine if something goes wrong during run. It’s modified to run about 175% of normal high pressure for very positive shifting. Just one piece of the puzzle in the build of that car…
Whatever she is…It looks BEEFY
Wow, @TwinTurbo, that is a very clever bit of re-engineering! You can build the engine to a narrower powerband and launch harder with all the ratio multiplication. And run a tighter torque convertor to boot!
By my calculator, a 2.48:1 first gear times 2.48 gives a 6.15 1st gear! That is a bunch of torque to the driveshaft. With a 4.10 rear gear that’s a whopping 25.2 times torque multiplication! Wow!
Very perceptive of you @Mustangman !
You’re absolutely spot on and the torque is massive. The brakes can barely hold back the car when placed into first gear. Often you get a squawk from the tires as they rotate a bit before the brakes can react.
The power train was designed from the ground up as a package. The engine is NA and can run on pump gas but is an animal with high octane fuel. It’s a punched out 454 w/cam, head and intake work that maximize pulse charging effects to achieve >105% VE (or more appropriately mass efficiency). It’s been dynoed around 575hp.
It can squawk the tires at 40 mph although it’s quite scary to do so as it gets a bit squirrely.
That output goes into this trans which is designed to withstand about 2x what it sees in this car.
When I built it I swore I should have used wing nuts, it was in/out so many times to get things right. I might have won the award for the broken hub club until I upgraded to billet, heavy duty hubs and haven’t cracked one since. As you can imagine the rear cross member is way back of its normal spot and the driveshaft is but a stub of its former self. I had a drive shaft shop do the work and they were like, what the heck does this go into??? All heavy duty parts there as well.
As you pointed out another advantage is in the torque converter selection. I must say, I am very impressed by your knowledge and ability to recognize all these advantages!!
That feeds into a beefed up 12 bolt that is located by an Art Morrison/Gazan package. It’s set to about 0.5 degree down and rises to neutral on launch. Custom designed progressive rear springs and she just squats a bit and goes.
The gearing is designed to get the mass moving and I’m out of first around 5 mph. But it launches like a beast with a bit of left side wheel lift when wearing slicks. And I can drive it on the expressway to the track if I wanted to (street legal tires of course).
Once I got it dialed in, I started getting more attention from the safety guys. After one particularly good run, they came trucking over and banned me from running again until I put in a roll cage. I had to draw the line on doing that to this car and so its days at the track were over…
You know you did yourself proud when the tech guys toss you for being too fast! The locals must have dropped jaws when that thing launched.
Sounds like you’d need an internal trans brake to hold back that monster!
105% volumetric efficiency is pretty impressive for a street driven big block Chevy… on pump gas, too! 575 hp is a big number but what kind of torque must this make? 590 ft-lbs? More?
Did you achieve that with a single 4 barrel (that would be impressive!) or duals on a tunnel ram or fuel injection?
The motor is fed by a Holley 4150 830CFM w/mechanical secondaries and choke delete. I did some work on the carb as well to beef it up a bit.
I have no idea what the torque ended up being but a line lock or better yet, trans brake would have been a welcome addition.
This whole thing started out as a challenge. I had been restoring Corvettes and got sick of walking up on people looking at my cars at local shows and having them disparage my choices and how they thought it should be done. Most of them didn’t even have cars but they had plenty of opinions.
I bought the Chevelle for something to drive while I was restoring another car. It already had a show quality paint job but the guy had made it into an SS clone which I started stripping off later on. I had dabbled in street night racing at the local strip and told my friends I would build a car I could drive to the track and blow their doors off. So I took the body off the frame and started working on it. I went a little overboard 
Smoothed frame rails and firewall, got rid of anything non-essential, hid all electrical, ran the fuel and trans lines inside the frame- I wanted it to look like just a crate engine sitting in there with no evidence of anything connected to it. It came out pretty good. Looked like a show car but had a mean side.
First time I showed up at the track, the guys are like- you’re going to risk racing this thing?!?
For awhile, I was running 3" exhaust to mufflers that ended under the car. Not the smartest thing to do but always ran it with the windows down to make sure I didn’t get gassed to death I wanted to get some NASCAR tips that turned out right before the rear tires but couldn’t find anything reasonable. Meanwhile, it had a rumble like a Harley on steroids. It would thump your chest just idling with a wicked stumble from the lumpy cam.
It was fun to take it to local shows and hear people from a distance- dude, this car has TWO shifters! and then they’d look below and like WTF??! is going on here?
The local boys knew me, the car was hard to miss but they pretty much left me alone because I wasn’t an idiot tearing up the place. One night, I went past a hamburger joint having an evening show and rousted it up a bit more than normal. Came back around and parked it off to the side. I look up and two cops are making a bee line toward me. Oh oh. I was preparing my speech when the one says- we heard you have TWO shifters in this car! Whew…
Here’s a pic of it at one point-
Weird, the pics got clipped. Here’s a wider view-
Ah, an old school hot rod from the days of my youth! I love it. Nice work. 
The pics are fine once I click on them. Very nice!
Ah JT if you agree with everyone,you can only be so wrong .no?(actually I thougt it might have been a Hydramatic )
That’s a great looking car. I love that wine red color and the graphics, too. Old-school Convo Pro (that’s what my memory says they called them…) wheels from Centerline.
Chevelles deserve big blocks. Big car, big motor, lots of room in the engine bay!