Hello Jim,

I have to admit that I don't know everything I should about all the versions of the OHC rear wheel drive transmissions Volvo made. There are some transmissions that we didn't get here in the US.

What year is your 1800? 1962-1968 with a hydraulically operated clutch or a 1969-1972 with a cable operated clutch?

Since your racing transmission is based on the M47, you are going to have to start with a later bellhousing than the 2 I have mentioned.

AFAIK, the only way to adapt a late M46 or any M47 to a B18/B20 is to cut the bellhousing and reweld it back together in the correct reclocked position.

There is a guy in The Netherlands who does this.

I have bought 1 of his adapter plates that reclocks the later B21/B23/B230 automatics to a B18/B20 for a customers car, but that modification does not require any welding.

Here is the website.

http://www.hukebasart.nl/huke/?Koppelingshuizen

FYI, Volvo did make a bellhousing that allowed an M45/M46 to bolt onto a B18/B20, but it only works on the early M45/M46s made up to 1978.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com