Thanks
Within that were 3 links back to the XFire Forum....
namely - SRT6_Roadsters process
https://www.crossfireforum.org/forum...ving-poly.html
over in CrossfireForum.org > Technical > Engine & Exhaust

however....
I do recall another where Timelord or someone made up a half inch ply wooden frame to accept the old casings and align the two metal halves perfectly for casting in the correct alignment. The wooden frame was going to do the rounds of a select few.