3 different years, same transmission, which one should I use?

[POPS6T6]

Currently in my garage, I have 2 transmissions, 1 is the stock transmission from the 1966 Barracuda w/273, then I have a 1968 318 with transmission attached, and lastly, my donor car is due this Saturday and it is a 1976 Duster with 318 and transmission.

Is there a difference/better one to use based on the year? I am going to rebuild the one I pick, I just want to start with the best possible core.

Thanks,

John

 

[OldVart]

I'll assume these are all 904 automatic transmissions. What engine will you be using in the Cuda? If memory serves me correctly, the 66 tranny's require a different torque converter because of a slight difference in the either the pump or the snout of the tranny. I'd go with the latest year you have to get away from little annoyances like that and you can then use a standardized torque converter. I'm sure someone with more knowledge of the 66 tranny's will jump in here and give you the absolute correct answer.

 

[Jim Lusk]

If the 66 trans is one that originally came behind a 273 four barrel, use it. Otherwise it won't matter much.

 

[POPS6T6]

I should have been more detailed in my post. I am rebuilding a 318 for my car, the 273 is the stock motor, and right now I am leaning towards hanging on to that just for old times sake.

Thanks,

John

 

[Mrmopartech]

well you either ahve 904 tranny,s or small block 727 trannys.What you should do is this.The 66 273 is going to be a 904,the other two can be either a 904/727,the 76 car could be a 727.If it was me,I would use the 727.But go under and look at each tranny pan and see which one has the square pan and which has the odd shape corner one,that will be the 727 tranny.Mrmopartech
Now that my old site is back up and running,go to mymopar.com to the tool reference section and look at the tranny difference.

 

[krabysniper]

For behind a small block, unless your going to be making 450 horse or more, I would stay with a 904, 727 robs horse power, I don't care what anyone else wants to say or claim, it robs horse power. There was a good article in Car Craft that discussed some of the pro's and con's of both. Here is a link 904/727 Car Craft article It certainly isn't the end all be all of info on the subject but it will give you some of the basics to help you decide for yourself.

 

[340mopar]

It is a reasonable article, especially since it is from chevy craft. But unless I missed it, it does say how much power is lost. I have heard all kinds of numbers, as much as 30hp and less that 10hp. There is no sense the article mentioning that something is more efficient if it isn't going to tell by how much. Anyone seen a test that has some real numbers? I would like to know.

 

[66dartgt]

Use the 76 tranny - it should be a part throttle kickdown unit which is preferred over the other two and will be a 904 unless it was messed with. The 66 tranny will have a small torque converter pilot hub and I think a smaller main shaft diameter, this will make hooking it to a later 318 troublesome. The 68 would be okay - but not have the part throttle kickdown. Ask any of the trans builders like A&A, they recommend the later part throttle unit. Save the 66 trans to match your 273 and set them together in the corner if you like. If your car is a 66 or older - the 727 is a tight fit in the dog house as well, for this reason the 904 makes more sense. In addition the driveshaft needs no mods to fit, and your trans linkage is a snap to install since it was a 904 orignally, just use the 66 linkage on the 904 you choose.

Enjoy !

 

[66dartman]

gotta agree with sniper. Use the 904 trans. Maybe all 3 are 904s. The 76 trans would be best choice as 66dartgt said. The 727 is a great trans, you just don't need it behind a small block. I built a 904 for behind my drag/street 360 and I love how quick it shifts. Besides, it fit without the sledgehammer in the tunnel.