Lockup converter compatibility

[chrysler kid]

I recently swapped a magnum 360 in my 78 cordoba. I have the correct balancer and flexplate with 360 magnum weights and ordered a nuetral balance 727 converter. Since the swap I have been having engine vibration at cruising speed that is driving me crazy. After exhausting all options I learned that in 78 they switched to a lockup transmission. Could this be causing my vibration and if so am I able to use the 46re lock up converter that came with the magnum motor or do I need to order a 1978 318 converter?

 

[oldkimmer]

Is yours a lock up? Then Use your magnum converter. But it shouldn’t matter. Did u put a lu 727 converter in? Did u have the driveshaft shortened and balanced? Kim

 

[Professor Fate]

A lock up convertor will not even fit a non-lock up transmission. Different input shaft spline count.
Do you still have the vibration in Park or Neutral if you match your cruising RPM? If yes, you have a balance issue in your engine/convertor. If not, the source of your vibration is elsewhere in your driveline.

 

[chrysler kid]

Is yours a lock up? Then Use your magnum converter. But it shouldn’t matter. Did u put a lu 727 converter in? Did u have the driveshaft shortened and balanced?

I have a lockup 727, but when I had the converter built I didnt mention that as I didnt know. Same driveshaft and transmission as I was running with the LA 360 I had in before.