I'm going to an 833 OD in my 426 wedge 64 Polara and I'm lookng at getting an extra bh to bore instead of my currnet one. What I need to know is how far can a 4.3" bore be opened before it gets into the pivot mount holes? The od bearing retainer is 5.1" I believe. Can the bh be opened that far or will I have to have the bh bored AND the br turned down? Thanks

The o.d. bearing retainer can be swapped for one that will

a) fit the bearing
b) fit the input shaft (18 or 23 spline)
c) fit the bellhousing as is
d) bolt to the case

This is a hell of a lot easier and likely cheaper than buying and boring a bellhousing. Check Brewers or Passons for the one you need.

I'm thinking this one from Brewers:

BR-696 BEARING RETAINER 4.805" DIAMETER 308 BEARING 23 SPLINE NEW CAST IRON Details

New cast iron bearing retainer for 1970-up B/E-body 23 spline transmissions with 308 front bearing, 4.805" outside diameter, 4.16" bolt circle, replaces cast #C99369 original retainer. Gasket and seal included
Price: $79.95

Ok, scratch that. I just noticed the year of car you're working on.

I'd go with a late model b/h with the larger bore and still use the above mentioned retainer. It'll still run you less than boring the b/h.

From what I've been told the 4.8" br bolt pattern is too small to fit the od trans, so either the bh has to be bored or the br turned down. I just don't know if the 4.3" bh can be opened up far enough.

So, if I get a 68-up bh with the 4.8 center register, all I need is the 4.8 br for the 308 bearing, then no maching is necessary on anything, right? I'd still like to onw if it's possible to bore the 4.3 bh out far enough to fit the 5.1 br without getting into the fork pivot mount holes....anybody familiar with this? Thanks again guys.