I have heard this twice, correct in some ways
went to Justins and had a look at his (at the time) and although one side matches up, the other did not
The cast engine block mount can be replicated to suit, but is a pain to get all the angles and required strength
whereas the SR block mounts are steel plates, you can trim them and reweld the base plate to the desired angle to suit
I cut the mounts off the crossmember and had angled plates made, that provide alot of strength against crossmember and used the sivia mounts
I have heard that someone on the forum has this done yes, i have not seen it or got pics, i could be wrong tho, i have not attempted this conversion with any car, so can't really say, but going off the above, be inclined to say not quite at this stage