So I am in the process of putting together a new .060 over 340 for the 69 Dart. Have the crank polished, everything checks out nice. Install the rods and pistons, camshaft, timing chain, lifters, yada,yada,yada. Everything painted nice Hemi Orange with new Eddy Aluminum heads, aluminum intake with an old set of M/T valve covers. Complete motor down to the alternator brackets. Remove it from the engine stand and attach it to the dolly I use to install motors from underneath. 727 Trans rebuilt painted and ready to go. Install the 3500 Fairbanks converter and attach the flex plate to the crank. I line everything up straight and start to bolt it up. Trans is 1/2" away from the block and torque converter is already locked tight to the crank. Finger tight 7/16 bolts in bottom of block only.
WTF????? NOW!!!!!!!
Loosen it back up and slide it apart and low and behold the crank was never drilled for a torque converter...
again WTF??????
Motor was removed from my 73 p/u before being rebuilt, which was a 4 speed.
Long story short has anyone ever ran into this????
Motor has to come completely back apart so the back of the crank can be drilled to accept a converter, as the converter is hub centric on the back of the crankshaft.
Man after today I can definitely confess to cussing while working on my car!!!

dont see how there could not be a recess for the converter nub.

540...
No 3 is what I think the problem is.
I know we used 273 rods and now that I think about it it is a 273 steel crank. But I never knew there was a difference in the converter snout. It is drilled for a converter but the diameter is only about 1 3/8" instead of about 1 13/16".

You got it, you'll need a TC with the early smaller OD & hopefully one of the trans/tc companies have something off the shelf. Well at least you dont have to go back into the eng

Yep, not all Mopar parts can be mixed and matched. Things changed over the years and that is one of them.

If it was only that simple. This is a build between myself and my dad of a re-creation of a 69 Dart drag car that he owned. He has a body and basically we use all of my extra parts to put it together. Its fine with me I will probably never build another small block car anyway. After I left this evening to go home and do a little research he calls me after I typed the previous post to tell me the crank is out of the motor and is ready to go back to the machine shop in the morning to be drilled. Seeing as how patience is supposed to be a virtue I sure hope it is because if its genetic I'm screwed...
1 step forward and about 200 back...

I don't want to rain on your parade but most 340 will not bore to a .060 very safely.Did you have it sonic checked? I've had one that I bored .060 and it developed a pin hole and leaked. If you used a 273 crank in a 340 I hope you had it balanced or it will shake for sure.

The earlier convertor will be a coarse spline and will not work in your tranny. Of course, you could send your convertor back and have it fitted for the smaller snout. Thanks for posting a picture of your Dad's car. When I owned it in the late 70's after Buddy Spataro repainted it, I never seen a picture of it in its race days.

Donnie Carns

Hey Quint, if you bake a loaf of bread at your house is it considered "inbread"? Just trying to make you smile for a second.

540.. The motor is a 69 block that has been together and running at .060 for a better than 25 years with no issues. I bought it in 1988 and put it in a p/u I had that ran 12.44@112. Motor sat for about 6 years and I freshened it for my 4x4 in 1995. Drove it until 2001 and motor sat for another 11 years. When we pulled it apart to check it out the bore was still good. I guess not being ran a lot over the years has saved it.
We replaced the rotating assembly with rods and crank that had been together in a 273 with low miles. everything checked out good at the machine shop so we used those. I never realized or noticed the opening in the back of the crank until time for the transmission.
It is a huge PITA but having the crank drilled to match the converter will fix the problem. We mic'd the converter snout and the back of another 318 crank to double check the diameter. By using the two it looks like there is about .005 difference in the crank diameter and the t/c snout. The machine shop said it isn't anything difficult to do.
Donnie...I thought there was something to the fact that the older 727 converters were different than the later ones but I didn't know exactly what the differences were. I didn't know you got the car from Buddy. I remember Nick talking about it yrs ago and said that it got wrecked when it was on a tow-bar or something on its way to Petersburg. I don't know for sure what ever happened to it.
Godscountry340...I'm not sure about being baked at my house but I know it is when baked at yours.... Get back to your honey-doos!! I know the wife has a long list of things you need to be doing.

Yes, I ran into the same problem quite a few years ago. I took a dremel with a grinding bit and I went around the inside of the crank until the converter hub fit fairly snug. Never had any balance issues or problems from doing that way. I know it is NOT the way to do it but I was taking a shot at it anyways.

I believe that it is only the early 904's that had a different snout from the later ones. The 727's are the same size, I believe. All the early 273's with an automatic trans were 904 equipped.

If the crank is from a small-register 273, the 727 flexplate should be a sloppy fit on the outside of the register.

If the flexplate fits the outside of the register properly and the converter hole is too small it might be a 4-speed crank that never had the converter register machined to final size....seen it a couple of times before.

My torque convertor books shows this: Early 904 TF 67 and prior use a 1.55" hub on the convertor. 68 and up 904 and all 727 TF use a 1.81" hub. You have an early crank machined for an early 904TF. You could machine the crank bore at a machine shop (engine disassembly) to 1.81" if there is enough meat which I think there is. Or just hand grind as it was suggested.

Donnie Carns

Did you balance the rotating assembly? IF not, it's gonna be way off (I think).

All of the parts are all internally balanced parts in a different combination. There was no balance of the rotating assembly done. Where would the balance issue come from? 273 crank and rods are internal. Fairbanks 3500 converter is a zero balance for a 340. Flex plate is a zero balance part also. Granted using the 273 rods creates a lighter bob weight but that is evenly distributed over all eight journals. If there is something I'm missing here someone set me straight before I re-install the crank.

You're correct that all the parts are internally balanced, BUT, the assembly was balanced to the weight of a 273 piston. I'm willing to bet those .060 over 340 pistons are a lot heavier than those standard 273 pistons that it came balanced with from the factory. Using those 340 pistons with the other 273 stuff will create an out of balance issue.

OOPS- gotta get back to the honey-do list.

Yup, the 340 pistons are heavier by quite a bit. Usually takes mallory metal to balance a 273 crank to a 340 (I hear it's expensive). 340 rods were also stronger than 273 units.

man these early 273' give everyone a headache sooner or later,

A little story to make you feel better and your entertainment as well.

7 years ago i purchase my 71 dodge challenger.

The transmission would always slip into 3rd gear.

One hot 100* i took the car for a drive and got stuck in bummber to bummer traffic,

I tooasted the Trans and it wouldn't gointo any gear.

Get the car towed home order myself a fresh 727 and a 2500 stall convertor that same day.

Next week end I get my transmission install the lines bolt up the transmission go to slide the convertor foward

Learned real fast about the early 273's that day

I missed that this is using 340 pistons on a crank balanced for 273 pistons (& the OE balance was not dead on at that). Plan on taking all 8 piston rod assy's in along with the crank

Quint, get it balanced. Mallory metal is expensive. We got a new crank for my son's car and an extra $300 was added just for the mallory metal plus drilling the crank for the mallory metal when we had it balanced. We had around $600 in balancing the crank itself (the rods, pistons, flywheel and dampener were already balanced).


Donnie Carns

to all who commented.

Pulled the balance of the motor apart today and loaded it up to get balanced. Converter, flex plate w/ bolts, crank, rods, pistons, balancer and bolt, everything less the front pulley. I sent an extra crank and the original 340 rods along that if the bob weights are too far off, he has other options rather than spending a small fortune on mallory. I also decided to have new rod bolts installed.
This like most other projects has gotten a little out of hand. What started as a ring and bearing freshen of a good running motor ended up being entirely different. It got a little bigger cam than expected, new pistons, Eddy aluminum heads, M-1 intake, MSD ignition, and a nice new set of Doug's 453 powder-coated headers. Now there are a lot of new parts involved that will undoubtedly produce more power making the initial idea of using the 273 crank and rods somewhat less desirable.
This combination less the 273 rods has been together for about 35k miles. I guess I used the 273 crank in 1995 when the motor was rebuilt, not realizing that it wasn't a 318 truck crank. The motor had no issues the whole time I had it in my p/u. Lord knows it got the snot kicked out of it all the time towing and messin around in the mud.
When removed 2 of the old pistons had a crack at the skirts so we replaced the whole set. The heads needed a lot of work involving new guides and valves and were going to cost about 700.00 so we ordered a set of iron replacement heads. After 3 weeks of waiting on the iron heads (backordered) the aluminum heads were purchased. Camshaft is a Racer Brown solid stick that has been in another 340 for over 35 years. I wanted to use it because I know it has no issues at all. Lifters and camshaft show no wear whatsoever and this thing just has an old school thump to it that is perfect for the car. After a phone conversation to Racer Brown valve spring rate required is just below that used on the Eddy heads. Seems to me the #'s on the cam are around 304-525 or something in that area. Racer Brown recommended going to a 1.6 ratio rocker to increase lift numbers.
In the end all I want is a dependable driver with some attitude that does not require racing fuel and is durable enough for an occasional flogging. Maybe I'm wrong but with a 3500 converter, 456 gears and 30" slicks it should run mid 12's all day, maybe a little more. Now after being balanced it should be a pretty tough little piece.
Donnie here is a pic of kinda where the car is now. Since the pic the windshield, back glass, head-liner,and black vinyl top have been installed. Rear 1/4 windows are in and done along with the package tray. We moved the battery to the trunk. K-frame and all front suspension is out now and everything will be installed in one shot from underneath. No hood removal required.... Thx all Quint

I got everything back from the machine shop. The crank was a 1968 318 truck steel crank, notice the small harmonic balancer. Turns out that the new pistons with the 273 rods we put in were a little lighter than the crank was originally balanced for. Now that everything is balanced it is back together again. Crank was drilled at the rear to accept the converter prior to being balanced. Now that everything is bolted back together here is a shot of long block on the dolly with the K frame, trans, headers, steering box, dist and plug wires almost ready to go in. I have a few more odds and ends to finish before I bolt this in as I don't want to have to lean over the fenders any more than I have to. I posted some other pics on the restoration forum of the dolly and the engine. Thx to everyone for the advice.