Round RAM vs V RAM bolt patterns

I have had an 70's M head on my 1942 Round Ram since I bought it 5+ years ago, and a 1J Vram setup on the shelf almost as long. It's time to figure out how to adapt the 1J to the Round Ram.
Why?
1) The M head has a B&S 7 collet and tooling is very limited
2) I got the 1J head and ram for $200, and it's R8.

I have read through several threads all over the web, and most people adapt the J head only to the ram. I have the entire V ram setup, so I'd rather use everything. Pics of what I have.

Here's the butt of the 1J setup, buried on the shelf.


I rough measured the bolt pattern between the 1J and the RR base years ago, and the pattern is different. I'd love to know what the exact measurements are. Anybody??


I figure making an adapter out of a riser might do the job.

Fire away/critique/enlighten. Anybody have experience with this adaptation? I have access to water jets, welders and another mill if needed to make the adapter.

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