"This was super helpful! Pin this post."
Thanks!
I'll put it in the 'Building an MBK sub...' sticky at the top of the rlx section.
"Can you put a clone or GEN 3xxx series movement in a 4-digit GEN case?"
Only a few will fit.
For example a 3035 with OPD dial will work fine in a 1500 case made for a 1570 date but a 3135 with OPD dial will not fit because it is thinner and the stem will not line up in the case tube. A four digit 16xx DJ is a mess because of the 'pie pan' dial and a flat dial (1016 etc) will work in some projects but I never tried it. The movement mounts a hair higher in a DJ 16xx case because of the 'pie pan' dial so a flat dial and 15xx without date works and calendar spacer might work.
There is quite a bit of difference in the 3035 and 3135...as a rule of thumb the 3035 is the same size as a 15xx date mvt but the 3035 and 15xx date movements are thicker than a 3135 and will not fit properly in a case made for a 3135.
Otoh...my first '1016' project used a no date rlx 15xx mvt without the calendar spacer in a 162xx case...this is the reverse of your question but it shows another possibility. Everything fits, movement, 1016 dial etc.
Since no one makes a 3035 clone afaik we are stuck with genuine 3135/3135 clones and ETAs for other than '21 jewel' projects.
What is needed is a pair of high quality automatic movements, one 19800 or 21600 bph with rlx 15xx dial foot holes and hand sizes and one 28800 bph with 3035/3135 dial foot holes and hand sizes. All 3035 and 3135 hands and dials will interchange up through the 36mm DJ etc but the bigger cases, DJ 41 etc use a movement spacer and the date is offset farther to the outside.
It's a moving target.