I use a Toyota W58 (Toyota box)/Dellow conversion in my 144 rally car. I’m very happy with it but I’ve heard of people being less than satisfied with the alignment.
A M46 or M47 is another option with the appropriate bellhousing. I got one from Holland (I can’t remember his name: maybe Huke Besart?) some years ago. I’ve never used it but it is well made. Or cut and weld your own.
