I'm so glad I came across this thread as it helped clear up a lot of questions I had in thinking about this swap. (I originally wanted to do the m20 e2i conversion, but I think the m30 would be a better platform to begin with for my purposes.)
I'd like to swap in the M30b35 but I'm getting confused between all of the links I've searched for and bookmarked. Thanks to everybody who contributed to the faq, It's pretty clear what needs to be done from the firewall forward, to include the ecu. None of it is too confusing for me. I just want to get some things clear and organized in a list before I start scavenging parts.
I have an 87 528e with the original manual transmission (I think its the g260/5). I don't mind using the e24 b35 or the e34 b35, it's really up to whatever I can find first. I can work around the engine mount discrepancy on the e34 b35. I don't mind using the e24, e34, or E28 SETA harness either, again that's pretty much whatever comes first.
What I can't find out if the original transmission in my 87 528e bolts to the b35. If it does, that's great. If it doesn't bolt up, I don't know if the bellhousing on my transmission can be swapped out with some other bellhousing to bolt up to the b35, (and if so, I don't know if I'd then need a different driveshaft.) < this is the most confusing and reading multiple links with conflicting info is making it worse
If my original transmission is too weak, but it'll bolt up somehow, im going to run it until it explodes while I find the better option which I understand to be the e34 g260/6, or g265? I haven't looked too hard on finding the info to swap in another transmission into the 528e because it didn't seem like something that had to be done out of necessity. If my transmission just won't work without a pointless, and likely custom adapter, would running the e34 manual transmission require a different driveshaft?
I'm sure this is covered somewhere too, but since I just thought of it this second, I'm sure I can get an e28 535i tachometer working in the cluster, or get a whole 535i cluster and somehow set the mileage to what my mileage is currently.