Best way to go engine/trans

[glovemeister]

I've got a 71 Challenger R/T that was originally a 383 HO, with I believe a 727.

From my understanding the stock trans needs a rebuild.

I originally thought the car was a 340 and finding such a motor is really hard. My plan was to go with a 318.  Since I verified it was a 383 I know those are easier to find. I would like to find a correct year or earlier 383 to put in there.

So my question is would a 318 swap be able to use the same trans I have? I assume motor mounts have to be changed?  Is there any difference between driveshafts of big blocks and small blocks?

Thanks,

[72hemi]

If your transmission in your car now is for the 383, then no it will not bolt up to a 318. The big blocks and small blocks have different bolt patterns.

[Tonker1]

So the car was originally a 383, it got changed to a 318 and now you want to change it back?

If your changing to a 383 from a 318:
You can use the 727 trans, but you would have to change to a big block bell housing to make the bolt holes line up.
Yes, the mounts have to changed.