Technical Need some tranny and rearend advice

Hey folks, my dad and myself are starting the design process of a 23t roadster and I need to expert opinions on the tranny and rear end set up that would work best for me. Were running a 472 Cadillac motor, which has tons of torque, so we need something that will

 

what?????????????????????/

 

Transmission wise you are pretty well stuck with a turbo 400 or use and adapter with a 700R4. The trouble is that most Cadillac turbo 400 had a very long tail shaft that is too long to use in most T buckets that already have a very short drive shaft.
Rear end the simple solution would be a 9 inch Ford although there are some newer rear axles that are pretty strong.
I have a 500 Cad in my ot truck and one thing to remember, even though you may have got the engine for pocket change hot rod parts for them are very expensive in comparison to other engines that are favored by hot rodders. Plus there are no T bucket style headers for them so you make your own or spend a ton of money.
I saw a guy driving an old Jeep body shell on a tube frame with a 500 Cad at Speedweek at Bonneville in 1998 that was a rocket sled on wheels though. He was just a spectator who had driven cross country but that was one fast car out on the highway.

 

thanks! I had thought about the 700r4 with the adapter. that may be the way to go. And the motor was running when we took it out. We are going to just freshen it up, and do the small stuff like a intake and maybe 3 deuces. We really don't wanna get into internal mods right now either.

 

Start with intro,after that use photos. As for your Q,your best bet is use a Cady rear an tranny if one can fit that new a engine 1967 that had FWD? Some Cady's guy with know?,
The only trick to rear is use rims with offset to put tires were you want.
Don't think 472 is smart in a T myself,anything can be done.

 

I'm not touching this thread......

 

Not sure where you are in your design process, but mentioned you know the Caddy is a heavy torque monster. It's fully capable of twisting up the typical T bucket style frame. Hope you take that into consideration before deciding to actually use it. If you want something different, think Chevy II or Quad 4, both of which dressed up are snappy T bucket engines.

 

why so?

 

why not smart? I see big block Chevys in T's all the time.

 

I'm set on the Caddy motor tbh. I love the look of those big blocks, and as far as size goes they aren't much larger and heavier than a SBC.

 

thank you all for the replies here

 

Yes, you do see big blocks in T buckets. Ever drive one? And I don't mean idle it to the car show and sit around all day looking at it. Take one out and drive it for a day. On something as light as a T bucket, a few pounds of unsprung weight here and there makes a big difference in how it handles. A typical 2X3 0.125" wall box frame with just a tube transmission crossmember will not be adequate for what you have in mind, so build accordingly. That's why I asked where you were in your design process you mentioned. I did not say it could not be done, but 95% of the ones that I have seen like you describe had terrible road manners. You will need a frame that doesn't flex much and has adequate bracing.

 

I don’t know, buckets are hard to drive even with a sbc in them. You jump on it to hard even shifting and they go sideways, ask me how I know that.

 

As to the threads title if that's what your set on be careful and ALWAYS use protection.

 

A build thread is definitely required! This I gotta see!

 

understandable. I'm deciding between Spirit and Ron Pope for the body and frame. I planned on more cross bracing as well. I think I read that Spirit builds their frames with 3/16 stock. Thanks again for the input

 

y'all got me thinking this is some crazy ass idea

 

A big caddy motor gets a big caddy moving pretty well with a TH400 and 2.7ish rear gears. Take 2/3 of the weight away, and it will get moving really well with the same drivetrain. No need for OD, with those gears. The Caddy is a low rpm torque monster. Take advantage of that fact.

 

Never seen tripower for that series of Cadillac engine.


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you are right...I was confused. We had originally wanted a 390 Caddy engine, and I believe they did offer a tripower intake. This 472 will just be the intake with maybe a diff. carb

 

I would NOT...bother with a 4spd. automatic trans. Especially the T-700-R4, (very low first gear !).
As you note, they have plenty of torque for pulling away from a stop, and don't need a lot of gear for highway cruising.

The first gear in a 4spd. will help twist a small framed chassis into a pretizel.

I'd stick with the T-400 or maybe a Switch-Pitch T-400.
Rear end wise, Dana 44, Ford 9". Gear wise, 3.55, (or maybe a 3.25).

Mike

 

100% agree with Jim, like always. For the th400 any bop case will work just find a short tail shaft and housing to shorten it up

 

I think you would be better off with Bonneville gears; 2.50:1 or something. That would somewhat tame the torque, it matches the RPM limits of the engine, and it would still have brutal acceleration.

 

those era caddy intakes do not have a water cross over. You can purchase flanges and build whatever you want. You will have to build a valley cover.
That engine makes so much torque you can get by fine with a short tail th400.
some 300 -275 ish gears and roast the tires off of it
https://www.hellsgatehotrods.com/shop/cadillac-big-block-425-500-intake-flange/

something like this


those engines are only about 75 pounds more than a similar equipped 350 chevy

 

They made several 400 turbos with the double bolt pattern, chevy, olds pattern. I think the caddy has the pontiac, olds type pattern if I remember right. 8.8 explorer rear end would hold up good, shorten the long side with a short side axle you'd be set. A friend of mine uses the gears out of Crown Vic and puts them in the 8.8, 2.73's or in that neighbor hood. You can buy ring and pinion from Quick Performance along with a install kit cheap, he sells good stuff, Timken or Toyo bearings. I've used a bunch of his stuff with no problems. I had a steel headed BBC in my A and it handled and steered great.

 

The 472-500 Cadillac is only about 60-70 lbs heavier than a small block chevy. You can shave some weight with a set of aluminum heads and aluminum intake as well.

 

I, for one, would not try to change your mind for a power plant in a small, light weight car. But, I’m crazy...
Just be mindful in your design to accommodate the torque. It can be done (I’ve done it and have the t-shirt to prove it).
You won’t need a lot of gear in it as people have said.
There are plenty of places where you can add strength in your frame. Think of the twisting dynamics to guide your placement of the tubing. You’ll probably be better off welding it directly to the frame and designing for a lift off body.
That’s what I’m doing with my present little T bucket (394 Olds power).
You can do this.
r


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Interesting, I don't recall ever seeing one of these.

 

Hmmnn, I thought all Tranny's had a good rear end.

Wait, hush...was that out loud?