There are two Weber Carbs that are
popular with Spitfire owners; DGV and
DCOE. Also available are DGEV (DGV with
electric choke) and DGAV (DGV with water choke).
DCOE carbs are sidedraft, meaning air goes
into the carb from the side as original SU's.
DCOEs are higher horsepower carbs but do require
much more tuning. Single or dual DCOEs are
available for Spitfires.
DGV carbs are downdraft; air comes in from
the top like the Zenith Stromberg carbs.
Although they can not achive as high horsepower
ratings, they are much easier to tune often
requiring no modification straight out of the
box.
See this link
for photo examples of these carbs.

Teglerizer's
Weber DCOE Pages
Paul Tegler built an exceptional page with huge
amounts of info on choosing, installing and
tuning Weber DCOE carbs. Also includes DGV
info.

Weber DCOE Service Manual
Josh Bowler's pdf of the DCOE service manual

Weber
DGV installation
Bob Owsinski's installation of a DGV Weber on
his 76 Spit

Weber
DGV Idle Setup
The page for general set the idle and idle
mixture on DGV and DGAV Weber carbs. Not
targeted to any specific model carb or car.

Weber
DCOE Setup
The page for general set up on DCOE Weber
carbs.

Weber
Setup
The page for general set up Weber carbs. Not
targeted to any specific model carb or car.

Weber
DCOE Setup on TR2-4
Though targeted to TR2-4, great info.

Weber
Carb Jetting Table
Jetting table for all major Weber carb
models and the cars that got them

Weber
DCOE Setup Page
Tuning theory of twin Weber DCOE or DCO/SP
carburettors

Weber
Carbs
Weber Tune ups from the Alfa Romeo Owners of
Oregon

Weber
Carb Identification Page
Views of many Webers to help identify which
Weber you have.

Weber
Carburetors: A Technical Primer
A basic, easy-to-understand introduction to
the world of Weber

Advanced
Performance Technology
Sells parts for Weber and most British
carbs

Emissions
and Crankcase Ventilation
A study and fixes for emissions removal

Oil
blowing from Dipstick?
This page explains why and the fix when fitting
DGV Weber carbs.