what crankshaft could i use?

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70Swinger

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since the forged 273 crank doesnt work with automantic transmissions, and im following the "mopar muscle magazines" 318 400hp build up. What crank would be best for an automatic trans?

Thnx Adam
 
in the magazine it says "the early 273 cranks have a different torque converter register, which creates problems in an automatic application"
 
See this car right here, it has a steel crank out of a '65 318 poly. It worked fine for the 727 converter.
I have lots of these cranks because people throw out these motors. I ask them if I can have it and they give it to me. I pull the cranks and toss the rest.
Your motor will have to be re-balanced because the Poly cranks are lighter (Oh Damn a lighter crank) I had to add a little weight to two counterweights even with the lighter Eagle SIR rods & old NOS TRW pistons (which are heavy in todays standards). So if you use the stock rods you will propably have to add more weight or get a lighter piston.
If you are only going to sling it to 5500 and 400hp I wouldn't worry about the cast crank.

Valiant.jpg
 
ever think about selling one of these cranks to a fellow mopar fan ahaha? i think im goingto go with rod that was used in 73 and up 318's and 360's, will they work with one of those cranks? and idea where i could get these rods ahah?
 
I've enver heard that, but I'll admit, I'm pretty ignorant of 273 stuff. But, you could simply order up a 318 crank kit for a '68 318. Then you'll get bearings you need for rod and main, a good crank that works, and all you need to do is internally balance it with your new rods/pistons. I priced a kit for a 360 last week and it was $200.
 
70Swinger said:
ever think about selling one of these cranks to a fellow mopar fan ahaha? i think im goingto go with rod that was used in 73 and up 318's and 360's, will they work with one of those cranks? and idea where i could get these rods ahah?
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I hate to be stingy but I think I want to keep the ones I have, These things aren't getting any easier to find. If you keep you eyes open you will find one. Watch the classifieds for people parting out a car or I got two motors from demo-derby guys that pulled the motors because they swapped in their "race motor".
I have a set of rods out of a 1973 340, actually it's they are the stock rods out of the motor in my Valiant. I would sell them for $65 + shipping, they are floating pin.
The rods and mains on the poly 318 are identical to the later 318.
 
the 273 cranks were fitted to 904 trans. the poly headed 318 were fitted to 727 trans. therefore, the back register is different between the two. find a machinist, have him bore the back register out to 727 size. it's done in a lathe. I know, I do them.
 
perfacar said:
the 273 cranks were fitted to 904 trans. the poly headed 318 were fitted to 727 trans. therefore, the back register is different between the two. find a machinist, have him bore the back register out to 727 size. it's done in a lathe. I know, I do them.
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How is it then that I have a '69 273 out of a Fury that had a 904 that is now in an '85 pickup with a 727?
 
whats does floating pin mean? im new to alot of this stuff, but im trying to learn as much as possible
 
A floating pin rod has a bushing in the small end and the wrist pin floats in the bushing. The wrist pin is held in with snap rings in the pistons. Most 318's have a pressed pin rod meaning there in no bushing in the small end of the rod with the hole being slightly smaller than the wrist pin. The wrist pin is held in the rod by being pressed in to the rod. I believe a 318 piston is available for a floating pin setup.
 
Because the 67 and earlier cranks had the smaller register. I am not sure about 68 and 69 cranks , but my 273 had the smaller register in it. I found out the hard way, after building a 727 and getting a torque converter, then realizing the delema.



340mopar said:
How is it then that I have a '69 273 out of a Fury that had a 904 that is now in an '85 pickup with a 727?
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don't know why your crank is that way, 340 mopar, apparently your're the exspurt. I only know what I have had to do to fix a problem. just tried to help the guy out. I can see now, won't do that again.
 
ta3834bbl said:
Because the 67 and earlier cranks had the smaller register. I am not sure about 68 and 69 cranks , but my 273 had the smaller register in it. I found out the hard way, after building a 727 and getting a torque converter, then realizing the delema.
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That's good to know, Thanks.

I thought I had a legitimate question why my 273 worked and perfacar said 273's must must be machined to work, meaning all 273's I must have used the wrong words or something because it set him off.

I appreciate your answer and I learned something new. We need more people with a helpful attitude like yours and less people flying off the handle just for asking a question.

perfacar I will be at Renegade this weekend for the first Summit race April 2 stop by and say hi. You will see that I am a decent guy and I am sure you are too. Here is my car you probably have seem it there. From your other posts it sounds like you have turned wrenches on the LemonTwister.

Valiant.jpg
 
ta3834bbl said:
Because the 67 and earlier cranks had the smaller register. I am not sure about 68 and 69 cranks , but my 273 had the smaller register in it. I found out the hard way, after building a 727 and getting a torque converter, then realizing the delema.
Click to expand...
So it must be that the '67 and earlier 904 must have a smaller center button on the converter and the '68 and newer 904 must have the same size center button as the 727? This must be why it worked on my '69 I'm guessing.
 
I don't turn wrenches on any cars., i just know certain people. i come out to watch, and see my friends race,
 
70 swinger
I prefer the floating pins. Thats what I use in my 273's and 340's. just use the good snap rings that are all one piece. pressed pins can come loose easier, IMO.
Dave C.
 
As far as pins go, full floating is preferred. It's easier to dismount and remount if you need to, and there's less of a chance of messing up with pin centering and heating the small end of the rod like apress pin. As far as cranks, I've seen 318 cranks go with 727s and 904s, but I cant swear that "all will work". '68 was the first year of 318s, and I think the cranks are the same thru '71. Later ones will interchange, as I think it's the balance (counterweight size) that varies.
 
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