Can I use a 67 904 on a 72 225 or is the crankshaft register hole size a problem?

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gregpurcell

gregpurcell

Greg Purcell
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I've opened this discussion up on a "wanted" thread (because I may need a new flexplate) but I thought I'd post it here also. I'd appreciate any advice from people who have done it!

I have a rebuilt 904 from a 67 slant (I think it's a 170). I need to put it on my 72 225.

I've been reading about the change in register hole sizes from 67-68 and most people say that you can't put a newer trans on the OLDER motor..How about the other way around?

Also, does the register hole size affect the flexplate? Will the 67 flexplate work on the 72 crank or do I need a post 68 flexplate?

Again, thanks for the advice! I want to have my ducks in a row before I pull it apart!
Greg
 
So. I spent the evening on Google and I may have found my own answer:
DART-08.jpg

Chrysler increased the diameter of the Slant Six (and small block V8) crankshaft flange register in 1968. You can put a later engine (1968-up) in front of an early 904 torque converter (1960-’67), but it is very important to use a machined aluminum adapter ring to assure perfect alignment. Ours came from Pat Blaise Transmissions (206/365-1966 or tflitepatty@comcast.net). Failure to include the ring will result in likely premature failure of the Torqueflite’s front pump bushing and/or seal resulting in massive ATF leaks. Folks hoping to match pre-’68 Slant Sixes with post-’67 Torqueflites are in for a rude awakening. The crankshaft pilot hole is simply too small to take the converter’s pilot nub. And forget about swapping torque converters, Chrysler changed the spline count of the input shaft after 1967. Grrr.
 
Greg, to use a 68 or newer engine on a 67 or older 904.
Use a 68 up flexplate, and the crank adapter/spacer.
I have both available, if you need them, Send me a PM.
 
Agreed. I bought one from Charrlie_S recently. Same deal for small block engines too, at the same year of change.

BTW, one can actually use a 68+ tranny with a 67- engine, if you change both the torque converter and input shaft on the tranny to 67- ones. At least I have read that. There were some later trannys that are desireable (like 999).
 
Thanks for all the help! I ended up lucking into a 74 Dart parts car, so I'll do the tranny swap from that (flexplate and all since mine is toast).
I have a 67 trans that was rebuilt at some point if somebody needs that.
Thanks again!
 
STOP and let's sort this out. You're about to spend $ on something that won't work.

Your question was putting an early motor onto a late transmission. This is harder. The hole in your crankshaft is too small, not too big. An adaptor ring can't work; it is made to put a late motor on an early tranny.

Also, you cannot use your early torque converter on your late trany. The spline count on the input shaft is different.

Here's your options:
- Swap your crankshaft for a later crank, or remove it and have the pilot hole drilled out to fit the later torque converter snout. You will need a late flex plate.
- Buy a modified torque converter. Hughes sells these for between $225 and $300 or so, depending on stall speed. They have the early snout on the front, but the late splines on the back to fit the late tranny. You will need an early flex plate.
-Sell the late tranny and find an early tranny/TC/and flex plate to fit the motor.
 
Oops; I just re-read the original post more closely. Like everybody said, early engine to late trans= no problem with an adaptor ring and late flex plate.

Like I said, early engine to late trans= harder, but can be done with the modified TC or a crank mod.:eek:ops:
 
Thanks for all the help, everybody! It's good to have this info BEFORE you pull your driver apart! By the way, here's a pic of the 67 flexplate stacked under the 74 flexplate. It clearly illustrates the difference in register hole size:
67flexplate3.jpg
 
I have done some research, and as near as I can find out, the 67/older small register flexplate, is not available new. The 68/newer flexplate is still available from most part stores. Any one looking for the early flexplate, do not believe the catalogs for the applicaton years. They show the same part number from 62-87, this is not correct. I spoke to ATP, Dorman, and Pioneer, about this. Dorman no longer does flexplates, ATP and Pioneer, had no clue as to what years fit what. Hell there tech guys probably weren't even born when the early part was still being produced. The engines that used that flexplate haven't been made for 46 years.
 
DustyRoads said:
Also, you cannot use your early torque converter on your late trany. The spline count on the input shaft is different.
Click to expand...
That is why I said you must change both the torque converter input shaft in the newer transmission to the older parts. I have read that, but never done it.

One might also machine the torque converter snout down, if there is enough meat there.
 
Charrlie_S said:
I have done some research, and as near as I can find out, the 67/older small register flexplate, is not available new. The 68/newer flexplate is still available from most part stores. Any one looking for the early flexplate, do not believe the catalogs for the applicaton years. They show the same part number from 62-87, this is not correct. I spoke to ATP, Dorman, and Pioneer, about this. Dorman no longer does flexplates, ATP and Pioneer, had no clue as to what years fit what. Hell there tech guys probably weren't even born when the early part was still being produced. The engines that used that flexplate haven't been made for 46 years.
Click to expand...
So if I order one from rock auto it should be the big hole for the 68+
 
Sorry, for dragging up an old thread..... but I have a 69 VF 225 that I want to rebuild and drop into my 67 VC with the 904 trans and tq converter .

I'm still confused if this is possible, and what special parts I need to make it work.

Also, if I'm going to be buying a new tq converter anyway, can I just order one with the right size snout so that it all bolts up together with no other mods?

Thanks for any advice.
 
Adam Berman said:
Sorry, for dragging up an old thread..... but I have a 69 VF 225 that I want to rebuild and drop into my 67 VC with the 904 trans and tq converter .

I'm still confused if this is possible, and what special parts I need to make it work.

Also, if I'm going to be buying a new tq converter anyway, can I just order one with the right size snout so that it all bolts up together with no other mods?

Thanks for any advice.
Click to expand...
I am not an expert on this but I did run into a bit of trouble with my wife’s ‘67 transmission in trying to find a high stall converter for it. The snout did go into the 360 crank, no problem. But the different spline count made a new converter impossible to find. I sent it out to a local place (Pro Torque) and they reworked the converter for me.

This is the pain and bane if these weird crossover years.
 
Thanks, that's good to know. never thought I would have trouble getting a torque convertor. will have to look into this, one that fits my 67 904 trans AND BOLTS UP TO a later 69 slant 6 motor...... otherwise no point starting the rebuild.
Thanks
 
Again, this was all spelled out for me in the beginning of this post but to reiterate; The crank hole (register) is smaller on the 67 and down and larger on the 68 up slant 6 engines. The "nub" of the converter is small on the 67 and large on the 68 up. The smaller nub fits into the bigger hole (with a spacer) but the bigger nub will not fit into the smaller hole at all (and the converters don't interchange). Therefore the 67/down trans will bolt to the newer engine but the later transmission will not bolt to the earlier engines. Several members here sell an aluminum spacer that slides over the small nub converter to let it ride in the later crank big hole without being sloppy.
 
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Adam Berman said:
Thanks, that's good to know. never thought I would have trouble getting a torque convertor. will have to look into this, one that fits my 67 904 trans AND BOLTS UP TO a later 69 slant 6 motor...... otherwise no point starting the rebuild.
Thanks
Click to expand...
There is no reason to spend the money for a special torque converter, for this swap, unless you want a high stall converter. If stock stall speed will suit your needs, just use the stock converter for the 67 trans, use a 68 up flex plate, and the crank adapter bushing.

PS: I sell the bushing for $25.00 shipped in the US.
 
Did you guys notice he's in Australia?
Just because things changed at a certain time in the U.S. doesn't mean it was done simultaneously down there. They had their own mfg plants down there so he may have to take some measurements.
SSD would probably know
 
I'm not following this . I'm dense sometimes I think I want to do this same thing but I'll ask it better . I have a 71 slant 6 ( a230 on it stock ) I have a 1968 904 we'd like to throw in it.

Is that the option of needing the spacer ?
What year converter and flex plate needed ?

Is this just not possible ?
 
Johnny71dusty said:
I'm not following this . I'm dense sometimes I think I want to do this same thing but I'll ask it better . I have a 71 slant 6 ( a230 on it stock ) I have a 1968 904 we'd like to throw in it.

Is that the option of needing the spacer ?
What year converter and flex plate needed ?

Is this just not possible ?
Click to expand...
It "can work" since later engines have a larger register hole than the torque converter snout of early 904's. But, I don't recall exactly when that changed. I recall between 1967 and 68 model years, and perhaps that year varied between slant-six and small-blocks. Since your transmission is on the borderline, best to verify once you get things apart (everyone should). If your transmission does have the smaller snout (unlikely), you can slide an adapter ring over it to match your engine. Charrlie_S here sold one to me, so see if he still stocks them or can make them. You can't just install a later torque converter since they also changed the #splines on the input shaft, though there are ways to Frankenstein that.

Another possible kink is that your engine was made for a stick-shift transmission and those crank holes can vary. I think they are the same diameter, but just deeper to fit the throw-out bearing, in which case the torque converter snout should fit. But, I've never dealt with a stick-shift, only read stuff here, so don't quote me and google, or hope someone smarter answers.
 
Adam!Remember that Chrysler Australia bought parts from america in batches and as VF was the last slant six in a Valiant they may have been earlier motors and come to think of it didn't later slant sixes have borg warner autos in the as well? Yes I know the brochures still called them torqueflites but I think they were BW35s !
 
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