My car has an a904 tranny from a 1978 Aspen. My new engine I want to install is a 170ci slant from a 1960's car. The 170ci motor was an ex-manual motor.

So yes, it doesn't fit. I know this is common sense to many people here, but for some reason I thought all slants were interchangeable.

Is there anything I can do to get these two to mate? I have tried Barry White already.

A custom torque converter is required. The pilot hole in engines prior to 68 was smaller than later engines. You'll need a torque converter with the small early snout and the proper size and spline configuration of the later transmission.

Some people have machined or ground down the later converter snout but I'm not sure that's a reliable fix.

Someone recently had a hybrid converter for sale. You might browse the For Sale forum and see if it's still available.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

If you can find a 904 with converter and input shaft from a 66 or 67 car and swap it into your later trans, that will work.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Wait a sec, guys; this one could be more complicated than that — a '78 trans is likely to be a lockup unit. That would mean the '66-'67 input shaft swap wouldn't work, and a "regular" hybrid torque converter also won't work. Has anyone ever had a small-nose lockup torque converter built? I don't know if it's possible.

It may be simplest in this case to machine the 170 engine's crank counterbore to the correct size for the larger (later) torque converter nose.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks for the input so far. I'm fairly sure it is a lockup unit.

I put a decent amount of money in to rebuilding the 170, and now that everything is together this is a little frustrating. I will ask around and take some pictures. I'm using borrowed space and tools, so I need to get this done.

The setup should have a decent amount of power. I have a T3/T4 hybrid turbo which I will be running at low psi. I'm going for gas mileage with passing/hill power. I want to drive the car and not have to worry about something breaking.

If all else fails I may be looking for a 4 speed swap. But I'm guessing finding a matching bellhousing for the old 170 would be another challenge.

Sounds like you're going to have to tear down the engine and have the crank pocket bored out to the later size to keep the automatic.

The bellhousing bolt pattern never changed. You can bolt up any slant bellhousing, but if you're wanting to use a 4-speed you can use either the late passenger car/light truck bellhousing that's drilled for 3 and 4-speed transmissions or the '64-'65 4-speed bellhousing. Of course you'll need a trans, shifter, clutch, clutch pedal assembly, clutch linkage, shifter, floor sheet metal and a flywheel with the small center hole to match your crank. Read the 4-speed article to learn about the 4-speed transmissions and the Clutch Overview to get up to speed.

Sorry you're finding out about this difference in cranks so late in the game.

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Joshua

Would it be unsafe to just grind down the torque converter to fit my smaller crank pocket? (as previously mentioned)

Do that and all the ATF messily leak out, and expose guts of the TC. This nub on that is part of torque converter mechanism and there is bearing inside it. It does not take much to grind thru.

Cheers, Wizard

The other option is simply get yourself an early transmission and converter. You lose the lockup, but it shouldn't hammer your combined economy. Just depends on what kind of driving your going to do.
With a 170, I don't think you'll see a marked increase in economy just due to the lockup. How heavy is your car?

CJ

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Part of Tyrde-Browne Racing

Good news. My local tranny shop is setting me up with a new custom Torque Converter for $250. They don't make them in shop, I'll get the name of the company that makes them.

They will take my core for the back side (lockup tranny fitment), rebuild and replace the innards with modern converter technology (I'm reading about that now), and weld on a new engine mount plate with the proper nub for a 60's engine.

*tilt*

What is this "modern converter technology" they say they'll be installing? Torque converters for Torqueflite transmissions are the same now as they've always been, plus or minus a bearing instead of a bushing here and there, but that's not "modern technology", that's just a durability upgrade.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

May-be "new" (asbestos-free) friction material for the lock-up clutch??
DD