Triumph Herald 1200 Twin Carb conversion

I have recently been sent a scanned copy of  - Triumph Herald 1200 Twin Carb conversion - part 511037 fitting instructions.  Here is a paragraph from the booklet.  The booklet was originally published by Standard Triumph and was scanned by Paul Cattrell.

TWIN CARBURETTOR CONVERSION KIT
Part No. 511037
Introduction
A twin carburettor conversion kit contains all necessary components
for converting a Herald "1200" engine of, 8,0:1 compression ratio, from
the single to the twin carburettor condition.
To achieve maximum performance conducive with safe operation of the
engine, when twin carburettors are fitted, existing main bearings, valves,
valve springs, ignition distributor and camshaft must be changed.
Existing cylinder heads must be machined to raise the compression
ratio to 8,5:1. Polishing the ports is unnecessary, but if undertaken care
must be exercised not to destroy the abutment faces for the manifold
locating sleeves.

The whole document is available to view and download from my box.com account at:  https://app.box.com/s/o3hq8rip7n2eo6wh6kgb54w145s6h5s6