something to look out for:

Apparently they are prone to cracks. Seems that the flat tappet blocks don't have the issue, so roller conversion of a flat tappet engine might be a safer option.

Found this while casually looking for 351 options. I'll probably stick with a 302 based setup in my beater if it ever comes to a swap since the GT40 (exploder) engines are plentiful around here.

quoted for ease of read:
Originally posted by strokeme
There is a cracking problem that is becoming an epidemic, and its only among the 351 roller blocks, the F4TE. We are averaging 2-3 cracked blocks for every 10 we get in. The crack is in the same spot every single time.

The cracks are noticed easily by eye when you remove the number 2 and number 4 cam bearing. Its not a coincidence that this is the same area that is used for the spider tray hold down. You can clearly see the cracks in the picture.

A problem will arise if this crack runs, the cam bearing will lose press and the bearing will walk out quickly and its all down hill from there.

I can guarantee alot of shops will use the block, whether they overlook it or think its not a big deal. I do NOT use these blocks. If you are having your roller windsor block machined, tell your machinist you want to see this area, protect yourself.