CDNCHALLENGER

Hi.

I am relatively new to the car hobby.

Is it possible to swap a 727 transmission that was in a big block car and put it in my small block (318) Challenger that currently has a 904?

Is there much involved or is it a straight swap?

Thanks in advance for your help.

Steve

ucfierocharger

I don't believe the bolt patterns are not the same, but on top of that...

you need to make sure the output shaft on the transmission is the same length, and you also need a different torque converter for the 727 (318 is internally balanced, so if you take one from a 340 or 360 it wont work). other than that, I believe it would just be a straight swap from a small block(318, 340, 360) 904->727

oh, and welcome to the forum!

CDNCHALLENGER

Thanks for the welcome and the reply.

I have a lot to learn so excuse me if some of my questions seem stupid.

Can you tell me the basic difference between the 904 and the 727. The 904 needs a rebuild but I have a line on a 727 as well. Just wondering if the swap is worth it.

Thanks again.

ucfierocharger

oh no problem, im fairly new to it as well. only had my charger for 3 years (and only 20 years old)

the 904 is basically a smaller 727. The 727 was used in the big blocks, like the one you have, as well as the performance small blocks such as the 340 and 360. the 318 went either way, some were 904 like yours, my charger has a 318/727.

Based on that information alone, if you plan on upgrading your engine to a 360 or adding performance parts to the 318 I would change to the 727 just because it's more heavy duty. since you have to take it out of the car to rebuild it anyways, might as well go for the 727 (check the bolt pattern on the bell housing and the length of the tail of the one you have).

I am actually rebuilding mine right now (i have a thread started in the DIY, no pics, but they will be coming soon) its actually not as hard as I imagined. Anyone with some simple mechanical skills should be able to do it with no problem.

CDNCHALLENGER

Hey,

Thanks again.

You seem to really know your stuff.

Steve

ucfierocharger

ive done a lot of reading on it. There are some really good online resources, and magazines have a suprising wealth of knowledge.

CDNCHALLENGER

Can you tell the difference between a 727 and a 904 based on the number of bolts on the transmission pan. My pan has 14 bolts. A guy at a local car show told me he thinks that 14 bolts is a 727 not a 904.

Any ideas?

ucfierocharger

I think they both have 14 bolts, but the 727 pan looks different than the 904. the 727 has a bulge on one side, and the 904 is fairly square. It may also say on the bell housing.

after a quick google search, yes they both have 14 bolts, but the 727 has the bulge that i was talking about

CDNCHALLENGER

My pan is fairly square so i will assume it is a 904.

Thanks again.

ucfierocharger

thats a good assumption. If you have a camera and want to take a picture. I can tell you for sure from the picture.

CDNCHALLENGER

I will do that.

Thanks

Doc

May I ask the REASON why you want to swap these transmissions?

Doc

It will NOT bolt-up ..... but I have to ask why ? ... if you race the car or are looking for mpg ... the 904 is a BESTer trans.