Yeah, I am still unsure if the R151 will fit on the 6 cylinder, as I have become accutely aware, not all bellhousings are the same!!!

Yes the bell housing will bolt directly on the gearbox, but are the INPUT shafts of the R150/R151 the same???

All R type gear boxes have the same bolt patterns on the front of the gear box and the tail, in addtion they all have interchangeable output shafts, the input shafts (do to varying gear ratios and length) are NOT interchangeable. This is something that I ran into and short of designing a custom bell housing you need to make sure that works out! If it was simple I would be using an R150 or R151 gearbox rather then the R154. (though the R154 allows for a much beefier clutch setup).

Jay