Thanks for all the help guys particularly the Heiko Ostmann contact, will try and track him down.
FIA 251 is the right form, I can't post the full version as it says file size exceeds limit of 300kb. Here is the link if you want it from FIA Archive:
https://historicdb.fia.com/car/de-tomaso-mangusta
The carbs are detailed page 6 lines 210 -213 and the inlet manifold and carb pictures are on page 13.
I wanted the 4 x Webers just for the hell of it, and the noise!
I'll keep the forum posted if anyone is interested
cheers
Larry
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