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m46 --> b21?

adamdrives

Member
Joined
Aug 9, 2010
Location
San Jose
I'm interested in manual swapping my 78 k-jet 242. A quick search says car came with the m45, m46 and m47 transmissions, but I believe the bellhousing is different on the older cars. Is that right? I'm having a hard time finding solid info. I've seen some adapter kits for b20 to m46, but I'm not sure which style m46. Or if the b20 and b21 outputs are the same. Never really gotten that deep into these older cars.

I'd just like a little more fun out of the car without going to crazy. Stock motor for now. What are my best options for putting in a manual box? Thanks in advance.
 
Standard "wrong coast" post lol...my '79 has an M46 and I have been considering swapping it to an auto as a gift for my better half who can't drive/refuses to learn a manual trans. I will be selling the M45 setup from my '78 though. Shipping would probably be a bitch though.
 
Any 240 series M46 from a B21F or B21FT car will work fine. B23F/B230F M46's have the wrong worm gear on the overdrive unit, so the speedometer will read comically high. Get the overdrive wiring, the clutch cable, clutch and brake pedal bracket, and the driveshaft from the donor. Grab a new speedometer cable from iPd or FCP, etc. Make sure it's one of the Cofle cables and not a Scan-Tech cable, though.

I'll shoot you a PM about it.
 
Okay, so front half and bellhousing will work from any m46, but OD unit and speedo cable output are different. Good to know.
 
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